Mar 01 2021

Book review: Guitar Method – Music Theory by Tom Kolb

music_theoryThis is less of a book review and more some notes on music theory as it applies to the guitar. It is based on Music Theory: Everything you ever wanted to know but were afraid to ask by Tom Kolb from the Hal Leonard Guitar Method series.

I’ve been playing guitar for a couple of years, and I found myself increasing asking why I am doing things and how are songs constructed. What notes belong with which chords?

The book starts with a tour of the fretboard, the version below is from the Youcisian website, I use Youcisian app for learning guitar – it’s great.

Kolb recommends learning the fretboard by picking a note and playing it up and down the fretboard at all locations. I have a new toy to help with this – a Polytune 3 tuner pedal!Guitar Fretboard Notes Diagram

I particularly liked the figure showing how notes on the traditional stave matched up to locations in guitar tab notation.

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P5 Figure 2 – how notes are repeated in traditional music notation and tabs

The observation that that the 5th fret on one string is the same note as the open note on the next string, except G to B when it is the fourth fret. This allows you to tune a guitar to itself, It seems like a useful cross-check. There was also a section on tuning using harmonics. I sort of got this working on my acoustic, I found I needed to watch a video: Justin Guitar – How to Tune Your Guitar using Harmonics to understand what I was trying to achieve.

The second chapter is on traditional musical notation, I feel I should know this but it isn’t a priority.

Chapter 3 is about scales and key signatures, there is an algorithm for generating the notes in a major scale. Figure 3 on p17 shows the C major scale in 5 locations on the fretboard.

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Page 17 – figure 3 the C Major Scale at different locations on the fretboard

There is similar expression to generate minor scales.

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Page 22 Figure 15 shows how the scale formula for major and minor scales compare.

Figure 13 (p21) shows how the C major and A minor scale compare

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P21 figure 13 the C major and A minor scales compared

p21-figure-14-a-minor-scales

P21 figure 14 the A minor scale at different locations on the fretboard

Chapter 4 talks about intervals (steps between notes) and their names. The names of the intervals are listed.

p25-interval-names

P25 table of interval names

Each fret on the guitar corresponds to 1/2 a step. The different intervals form different patterns on the fretboard, these patterns are moveable but they change around the G-string because the interval to the G-string is four steps rather than 5.

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P26 figure 5 interval shapes on the top strings

p26-figure-6-interval-shapes-bottom-strings

P26 figure 6 interval shapes on the bottom strings

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P28 A list of popular songs illustrating the intervals

Chapter 5 introduces us to triads which form the basis of chords. The pattern for major triads is 1-3-5 and that for minor triads is 1-flat 3-5. Augmented triads are 1-3-sharp 5 and diminished triads are 1- flat 3 – flat 5

Chapter 6 – harmonizing the major scale chords are related to scales via the process of harmonisation. The chords of a scale are given Roman numerals with the case indicating whether they are major or minor chords, and a o superscript indicating the diminished vii chord. The chords for the major scales are shown in the figure below

p36-figure-3-harmonized-major-scales

P36 Figure 3 Harmonized major scales

Jazz, blues and other music styles use 7th chords which add a seventh to the 1-3-5 pattern. This produces a harmonized chord table which looks like the above but with a 7 added to each chord! Actually the I and IV chords get a maj7 and the V chords just a 7.

Chapter 7 following on from the harmonized major scale get to construct a whole load more chords with different names by modifying the basic 1-3-5 formula.

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P41 Chord names

Power chords are unusual in that they are comprised of only two notes 1-5, the rest are three or more. This does not say anything about the voicings of a chord, the exact notes on the fretboard which are played. Slash chords are sometimes just simplified names for chords which have a complex formal names. There are polychords, indicated by one chord name over another, like a fraction which suggest two chords played together they are not very relevant to guitarists.

Chapter 8 – we can repeat the exercise of harmonising the major scale for the minor scale. This changes the pattern of major and minor chords. Relative scales such as C major and A minor use the same chords but they take different roles in the chord number sense.P50-relative-scales-harmonized

P50 Figure 3 shows how the Roman numerals and chords of the A minor and C major scale relate.

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P50 Figure 4 shows the harmonised minor scale

Chapter 9 if we know the scale a set of chords belongs to in a song them we can play notes from that scale as a solo over it. Progressions often start and end on the I chord so we can use that as a clue, and the V chord is distinctive too this seems to be because it is the "dominant" chord. Popular music often sticks with one key centre but other forms of music such as jazz can switch from key centre to key centre but they usually return to the original key centre.

Chapter 10 – the blues doesn’t follow the same scheme as discussed to this point. There are a number of different standard blues progressions based around the I, IV and V chords. The blues makes a lot of use of the minor pentatonic scale

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P63 Figure 8 Formula for the pentatonic scale along with the major scale for comparison

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P63 figure 9 A minor pentatonic scale at different positions on the fretboard

The blues scale has a different formula again, handily the formula and the scale at the 5th and 11th frets are shown in the same figure for the A blues scale. We should play notes from this scale of the A7(I), D7(IV) and E7(V) chords.

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P64 Figure The blues scale formula with positions on the fretboard.

There is also a major pentatonic scale.

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P64 Figure 12A The formula for the C major scale and the C major pentatonic scale, compared

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P65 Figure 12B The C major pentatonic scale at different places on the fretboard.

To make matters more confusing it is not uncommon to mix the major and minor pentatonic scales with the same root together (parallel scales)!

Chapter 11 covers the modes of a scale. Modes of a scale use the same sequence of notes but with a different starting note because they use the same notes they differ from the scale starting at that note. The modes have names Ionian, Dorian, Phyrgian, Lydian, Mixolydian, Aeolian and Locrian.

P68-scale-modes

P68 Figure 3 the modes of the C major scale and their notes on the fretboard

The chapter covers each mode, showing formula (notes), construction, category (major, minor etc), differentiating scale degree. chord types, harmony (Roman chord numerals), and common progressions as well has patterns on the fretboard.

Chapter 12 other scales and modes, this starts with an encyclopaedia of further scales, such as the whole tone scale and chromatic scale, showing information similar to that shown for the standard modes. This chapter includes information on arpeggios and how chords relate to scales.

Chapter 13 chord substitution and reharmonization. These appear to be ways of modifying chords, either by changing or adding a note or by substituting chords in a progression. What chords can be substituted for which depends on the family the chord lies in (Tonic, subdominant, dominant). This is one of those places where the function of chords are hinted at, tonic being something that "resolves" the key, IV chords move away from the tonic and V chords move towards it.

p88-figure-2-chord-families

P88 Figure 2 Chord families illustrated for the C major scale.

I find it useful to think in terms of computer code, what information do I need to generate the fretboard, scales and  chords.

  • Fundamentally we need the notes A-A#-B-C-C#-D-D#-E-F-F#-G-G#
  • From the notes we can generate the fretboard given there is a half step per fret and the notes on the open strings (E-A-D-G-B-E) – it would be interesting to know which octave a note sits in;
  • Using the scale formula I can generate the major, minor, major pentatonic, minor pentatonic and blues scales from the notes;
  • Given the harmonisation of a scale I can get the chords in the scale;
  • Given the chord compositions (i.e. 1-3-5) I can generate the notes in a chord and the names of the chords;
  • There’s probably an interesting exercise in generating chord voicings and scoring them for playability and sound;
  • Finally, we can calculate the modes of a scale;

Missing from Music Theory is much description of the "function" chords, these are hinted at in terms of returning to the root chord and resolving tension. Chord progressions and song structure are also not covered.

It seems like the next steps are looking at some of the songs in my songbooks, or tabs on Songsterr and working out which chords are being used and hence which scales, and what the chord progressions are. I should also be able to work out which scales riffs come from. It would be good to learn about song structure too.

Feb 19 2021

Book review: Exercises in Programming Style by Cristina Videira Lopes

exercises_in_programming_styleRecently our CIO has allowed us to claim one technical book per quarter on expenses as part of our continuing professional development. Needless to say since I was buying these books already I leapt at the opportunity! The first fruit of this policy is Exercises in Programming Style by Cristina Videira Lopes.

The book is modelled on Raymond Queneau’s book Exercises in Style which writes the same story in 99 different ways.

Exercises in Programming Style takes a simple exercise: counting the frequency of words in a file and reporting the top 25 words, and writes a program to do this in forty different styles spread across 10 sections.

The sections are historical, basic styles, function composition, objects and object interaction, reflection and metaprogramming, adversity, data-centric, concurrency, interactivity, and neural networks. The section on neural networks breaks the pattern with example programmes only handling small elements of the word frequency problem. The sections vary in size, the objects and object interaction is the largest.

Lopes talks about styles in terms of constraints, for example in the "Good old times" historical style there are no named variables and limited memory, in the "Letterbox" style objects pass messages to one another to prompt actions.

The shortest implementation of the example is in the "Code Golf" chapter with just six lines, other examples run to a couple of pages – a hundred lines or so. Lopes is somewhat opinionated as to style but quite balanced providing reasoning where unusual styles may be appropriate. This was most striking for me in the section on "Adversity" which discussed error-handling. Lopes suggests that a "Passive Aggressive" style with error handling all occurring at the top level in a try-except block is better than my error handling to date which has been more in the "Constructivist" (trapping errors but proceeding with defaults) or "Tantrum"(catching errors and refusing to proceed) style.

Sometimes the fit to the style format feels slightly forced, in particular in the chapters relating to neural networks but in the Data-Centric chapter I learnt how to implement spreadsheet-like functionality in Python which is interesting.

I’ve been programming for about 40 years but as a physical scientist analysing data or trying out numerical models rather than a professional developer. Exercises  brings together many bits and pieces of things I’ve learnt, often in the context of different languages. For a while I’ve had the feeling that I didn’t need to learn new languages, I needed to learn how to apply new techniques in my favoured language (Python) and this book does exactly that.

Once again I was bemused to see Python’s "gentleman’s agreement" methodology over certain matters. By convention methods of a class whose name start with an underscore are considered private but this isn’t enforced so if you really want to use a "private" method just go ahead. Similarly many object-oriented languages support a "this" keyword for the members of a class to refer to themselves. Python uses "self" but only by convention, you can specify "self" is "me" or whatever other name you please. The style format provides a nice way of demonstrating a feature of Python in a non-trivial but minimal functioning manner.

It is somewhat chastening to discover that many of the styles in this book had their abstract origins in the 1960s, shortly before I was born, entered experimental languages such as Smalltalk in the seventies where I would have read about them in computer magazines and became mainstream in the eighties and nineties in languages like C++, Java and Python, not long after the start of my programming career. Essentially, most of the action in this book has taken place during my lifetime! In physics we are used to the figures in our eponymous laws (Newton, Maxwell etc) being very long dead. In computing the same does not apply.

What I take away from Exercises is that to a fair degree modern programming languages can be used to implement a wide range of the ideas generated in computer science over the last 50 or so years so in improving your skill as a programmer learning new languages is not the highest priority. There is a benefit to learning new techniques in a language in which your are familiar. Clearly some languages are designed heavily to support a certain style, for example Haskell and functional programming but I found it easier to understand monads explained in the context of Python than in Haskell where everything was alien.

Exercises is surprisingly readable, the programs are well-documented and Lopes’ text is short but clear with references to further reading. It stands alongside Seven databases in Seven Weeks by Eric Redmond and Jim R. Wilson as a book that I will rave about and recommend to everyone!

Feb 05 2021

Book review: Entangled Life by Merlin Sheldrake

entangled_lifeEntangled Life by Merlin Sheldrake is a book which came to me via my wife, as she read it she kept providing me intriguing nuggets of information about fungi so I thought I would read it next. For the older reader Sheldrake might be a familiar name, his father Rupert Sheldrake was something of a character perhaps best known for his theory of morphic resonance.

Entangled Life is not a dry, systematic study of fungi but rather a rambling exposition with much biographical detail. Each chapter contains a good description of some facet of fungi, alongside some broader discussion of the people and places Sheldrake visited to write the chapter and musings on the broader meaning of the facet.

The first chapter, entitled "A Lure", is on truffles, looking back this chapter is designed to entice us into reading further by talk of a very financially valuable, and desirable fungi. Sheldrake takes us to the woods of Italy for a truffle hunting trip providing scientific detail alongside the human story.

Next comes "Living Labyrinths", inviting us to change our mindset about how an organism is put together. Fungi are not like plants or animals, they are a network composed of hyphae. Different fungi have different network structures, and the hyphae in a network can be arranged in different large scale structures such as chords and rhizomorphs. The mycelium network can transport substances over distances, and also signals, although it isn’t clear how they do this. Mycelium networks can "solve" maze-like problems, I’ve seen reports of this in the past and I don’t see it as evidence of intelligence – essentially the networks solve a diffusion problem by using diffusion. They are a type of analogue computer.

"The intimacy of strangers" introduces us to lichens – fungi-algae symbionts. The structure of lichens and symbiosis were discovered in the second half of the 19th century. The discovery was something of a revelation, previously there had been organisms and their parasites – none of the cooperation that symbiosis is founded on. It is fair to say we are still learning a lot about lichens, including the fact that the partners in lichens can be quite fluid. Lichens challenge our ideas about what it means to be a species.

"Mycelial Minds" is definitely the most terrifying chapter – it details how ophiocordyceps takes over carpenter ants and has them behaving in very specific ways (climbing to a high point on a stem and waving their legs around) for the furtherance of the fungi. Also discussed in this chapter are LSD and the Psilocybin mushrooms, fungi or their derivatives that are psychoactive in humans.

"Before roots" covers the long standing relationship between plants and fungi – it is proposed that it was fungi that hauled plants out of the waters and onto land, hundreds of millions of years ago. Fungi specialise in accessing minerals locked in rocks, and the remains of lichens would have formed the first soils on land (they still do, when new land from volcanic activity or otherwise is exposed). This would have provided water-borne plants with a mechanism for accessing nutrients on dry land. Fungi still form a critical partnership with plants, extending and enhancing the plant’s own root network in exchange for energy derived from the sun by photosynthesis – fungi cannot photosynthesise themselves.

"Wood wide webs" talks about how forests are knitted together with mycelium networks which link one tree to another, and another. In a small patch of woodland one tree was found to be linked to 47 others via the mycelium network. The mycelium network can transmit some of the plant distress signals as well as moving nutrients from one tree to another. In some ways Sheldrake dislikes the reference to the Wood Wide Web because it sees the trees as the "servers" in network and the fungi reduced to the lowly cables and routers.

"Radical mycology" – the science side of this chapter is the development of fungi for the remediation of pollution and producing recyclable "green" materials. It starts with a discussion on the coal measures laid down in the Carboniferous period – this was a time when the mechanisms for decomposing wood were limited. Since then fungi have evolved which are efficient in degrading lignin – a key component in wood – this is a rare skill. The human side is the longstanding mycology counter culture, fungi have not had a high academic profile but have attracted an enthusiastic amateur following initially interested in psilocybin mushrooms but now more generally involved in research and discovery.

"Making sense of fungi" – the scientific element of this chapter is around fungi particularly their use in making alcohol. I was intrigued to learn of the "drunken monkey" hypothesis of our taste for alcohol – essentially our ape ancestors used alcohol as an indicator to find ripe (or even over-ripe fruit). Humans have a mutation in an enzyme which enables them to process alcohol, otherwise it would be (more) toxic to us – they evolved this ability before they started deliberate fermentation to make alcohol.

One of the recurring themes of this book is how relatively little studied fungi are, they don’t fit into our neat, longstanding picture of the living world consisting of plants and animals, and individuals rather than symbionts being the fundamental unit of biological thought.

I found Entangled Life a fascinating and enjoyable read, and I didn’t even have to buy the book!

Jan 16 2021

Book Review: History of Britain in Maps by Philip Parker

history_of_britain_in_mapsI’ve always been a fan of maps, so the History of Britain in Maps by Philip Parker is right up my street.

The book is ordered chronologically with each map getting a short page of text facing a page of the map, with some maps earning an additional double page spread. Except for the earliest periods the maps are contemporary.

The book has the air of written as a set of separate map captions with some repetition between maps relating to the same period.

There are some recurring themes through the book, maps for the pleasure of maps seem to play a role, as do military maps showing defensive positions or explaining military actions. Maps of ownership are also common. Finally there are maps for travel, first by road and then later by canal and railway. Also apparent is the evolution of mapmaking skills.

Aside from the exceedingly schematic representations of Britain on the Roman Rudge Cup from 130AD the earliest maps of Britain date to the medieval period and Matthew Paris, a Benedictine monk who was active around 1250AD. There are religious Mappa Mundi from slightly earlier but Britain is very much on the edge of these schematic representations of the religious world with Britain perched at the very edge, if visible at all.

The earliest map of Britain that looks like a map is Matthew Paris’s map of 1250AD. The shape of coast is heavily distorted but some names recognisable to the modern eye appear (such as my home county of Dorset). Rivers are prominent most likely because they were the key method of transport over longer distances. There is a strand of maps that portrays the nations of the British Isles, the counties within them and cities, particularly London which are about place, belonging and power rather than navigation or even defence. Towards the end of the 16th century such maps start to look very much like modern maps, they are relatively accurate and follow modern mapping conventions (rather than being panoramic views or schematic views).

Also produced by Paris is an "itinerary map" showing the progression of towns a pilgrim to the Holy Land would pass through on their trip from Britain. This type of map is a recurring theme through the book, it is not interested in the details of the landscape, it is not a plan view, it is a linear track with distances. This is highly relevant to the traveller who is constrained to travel along the roads rather than view the landscape from above, as a bird does. In some respects this path turns full circle with Beck’s highly schematic but very clear London Underground map.I was interested to learn that road signage was not introduced until 1696.

Although there are earlier examples of coastal maps Henry VIII’s dissolution of the monasteries in the 16th century which led to open season being declared on Britain by the Pope, produced a number of coastal maps of the South of England. These are a recurring theme. The monarch, and his counterparts in Europe, were both keen to map the defences of the South Coast. Similar maps were produced during the Napoleonic Wars and the Second World War. Also falling into the military remit are the various maps of military engagements of the Civil War. The earliest work of what was to become the Ordnance Survey in Scotland in the mid-18th century and then in Kent related to military interests (the clue is in the name).

Maps of ownership are another recurring theme, these start in the early 15th century typically establish the land and rights of the monasteries. Later maps, in the early 19th century, show the results of the Enclosure Acts which took from Common land from everyone and gave to the wealthy now-landowners. Similarly the tithe system whereby a tenth of the produce of an area was owed to the parish was converted to a land taxing system where money was given instead.

There are the 19th century "social" maps of cholera by Jon Snow’s, deprivation by Charles Booth and the census of 1841 by August Petermann. Fi

The book ends with a map of the votes cast in the 2016 EU referendum, a bitter topic as I write in January 2021. 

Obviously as a fan of maps, I enjoyed this book. It is a nice skim through British history if you don’t want anything too heavy going, it is also a good overview of what types of maps people were making and when. I’d seen quite a few of the maps shown in other books, you can get a flavour of these here on the maps tag of my blog.

Dec 31 2020

Review of the year: 2020

It’s been a bit of a year!

On the scale of things we were pretty well situated, my wife and I both have jobs which can be done online effectively although Sharon’s university employers, in common with many universities, had an unwarranted enthusiasm for maintaining some face to face student contact and getting students on site.

We have a moderate sized garden where Thomas (now nearly 9) and I played a lot of football, touchingly (and rather naively) he thinks I should be a professional football player! Thomas and I also did quite a lot of baking together. Home-schooling was a battle of attrition, Sharon took the lead on this, for which I am eternally grateful. My part was largely the baking which we passed off as "maths". Thomas took the philosophical view that home was not school and we were not teachers therefore there could be no home-schooling. By the end, and in common with many parents, he was spending most of his time watching videos and playing games on a tablet but we made it through and he is now really happy to be back to school.

me_and_thomas

We live next door to a supermarket which was handy particularly in the early days of lockdown when there were shortages of random food items, and often queuing to get into the shop. As a result of covid, and the forthcoming final exit of the UK from the EU, we now have a second freezer and a moderate stockpile of food.

We are on the edge of Chester, so we can walk from our front door into the countryside. I also discovered cycling for leisure again, and found the routes out along the Greenway and back along the River Dee were rather good – car-free, well-paved and almost entirely flat. I also cycled out to Ness Gardens as part of my company’s annual "challenge", any "challenge" that involves coffee and cake at the mid-point is fine by me!

This years blogging has been thin but rather more varied than usual, I found I had less time for reading than normal. The traffic to my website has increased this year though, presumably because people have more time on their hands.

I wrote a couple of technology blog posts (Type annotations in Python and Unit testing in Python), these are pretty popular – I guess people are often googling for just the problem I have been seeking to fix.

I attending some counselling sessions for anxiety earlier in the year, so obviously blogged about that. Coronavirus has not been a problem from an anxiety point of view (other than the normal anxieties everyone else has!): I have been largely forbidden from doing the things that made me anxious!

Since I was spending more time in the conservatory, playing drums and guitar, I gave it a bit of an upgrade. I also wrote a rare "Gear review" post about the Boss RC-3 Loop station – it’s a guitar thing!

On the book front You look like a thing and I love you by Janelle Shane had me sniggering quietly to myself reading it on the train, it’s an overview to machine learning mainly focussed on the often hysterical results of machine learning. I read How the states got their shapes by Mark Stein, followed by 1491 by Charles C.Mann about pre-Columbian civilisation in the Americas. The Black Lives Matter movement reached the UK, and I was rather proud to see the residents of Bristol (one of my home cities) chuck a statue of the slaver, Edward Colston, into the harbour. My actions on BLM were modest, I deliberately started followed people who weren’t like me on social media, and read Black and British: A Forgotten History by David Olusoga – this has helped me think differently about British history. Also by David Olusoga (and Melanie Backe-Hanson) I read A House Through Time and related to houses, I read The Address Book by Deirdre Mask.

Along the lines of my more usual reading in the history of science I read The Egg and Sperm Race by Matthew Cobb – which is about how we came to understand reproduction in animals (and humans). The Pope of Physics by Gino Segrè and Bettina Hoerlin – about Enrico Fermi, Science City by Alexandra Rose and Jane Desborough – about science in London, The clock and the camshaft by John Farrell – about technology in the medieval period, who would have thought hammering was so important! Finally, and a little unclassifiable were  Sea monsters on Medieval and Renaissance Maps by Chet van Duzer and Your voice speaks volumes by Jane Setter.

We didn’t really manage a holiday away this year, we visited my father-in-law in Malvern for a few days but various restrictions and our caution made anything more an impossibility. Here we are climbing up to British Camp on the Malvern Hills

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Thomas learned to ride a bike! He’s not shown much interest until now, we bought a cheap second hand bike from Bren Bikes and he was riding without support within a couple of hours.

As an end to a poor year my dad passed away a week before Christmas. He’d moved to a care home in January this year following the death of my stepmother a little over a year ago. Initially rather ill, and a little confused, his health improved as the year progressed. By lockdown he had started making short trips out on the train. In lockdown he engaged with the social life of the care home, and was making daily walks around the garden but towards the end of the year his health was declining. He died rather suddenly on Thursday 17th December, my brother had seen him the previous Saturday. We are grateful for his mercifully quick end, and the final year he had. I wrote an eulogy which you can find here. The funeral was held on 30th December with most attending online, as many have done through this year – I posted the Order of Service here which includes the music, readings, eulogy and photos.

A picture of dad with Thomas and Sharon

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My winter gloom is not so bad this year because I’m not cycling to and from work in the dark, obviously circumstances have made it a rather sad end to the year.

I guess all that can be said now is "Here’s to a better 2021!".

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