# Continuous Line Artist view of Haken’s Gordian Knot.

Depth of lines in black and white, in Haken’s Gordian Knot. Mick Burton, single continuous line drawing 2015.

Here is an update on posts which I did in May and June 2015 regarding the above Knot and the interest these posts have since generated.

As a Continuous Line Artist I have looked at many angles of what my lines may mean and what they can do.

One such examination was triggered by Haken’s Gordian Knot, a complicated looking knot which is really an unknot in disguise – a simple circle of string (ends glued together) making a closed line, which I saw in a book called “Professor Stewart’s Cabinet of Mathematical Curiosities”.   The drawing above is my version of Ian Agol’s illustration of the Haken Knot (see it in my post of 31 May 2015).  I used dark and light shades to emphasize the Overs and Unders shown for the line.

The reason that I was so interested was that it reminded me of my “Twisting, Overlapping, Envelope Elephant” (see below).

This single continuous line drawing is coloured to represent a “Twisting, Overlapping, Envelope Elephant”, which is Blue on one side and Red on the other. Mick Burton, 2013.

How this elephant line works is explained in my post of 31 May 2015.  In essence, you need to imagine that the composition is made up of a flexible plastic sheet which is Blue on the front and Red on the back.  Each time there is a twist, on an outer edge in the drawing, you see the other colour.

In the Gordian Knot, I spotted that there is a narrow loop starting on the outside (lower left on first illustration above)  which seemed to lead into the structure, with its two strands twisting as it went, each time in a clockwise direction.  I followed the two twisting lines throughout the drawing until they ended in a final loop on the outside (left higher).  I counted 36 clockwise twists and one anticlockwise.  My thoughts are explained in full in my post of 2 June 2015.

To aid the explanation I completed a painted version, where I used the same Blue and Red colours, as for the above elephant, to emphasize the twists.

Twisting, overlapping colouring of Haken’s Gordian Knot. Mick Burton, single continuous line drawing painting 2015.

Note that the colours in the Elephant define two sides of a surface, but in the Unknot the colours are illustrating the twist of two lines travelling together.  The twin lines go through other loops continually so there are no real surfaces.

After completing the above two posts, I decided that I would try and find out more about the Knot and came across a question posed by mathematician Timothy Gowers, in January 2011, on the MathOverflow website.  He had asked for examples of very hard unknots and after many answers he had arrived at Haken’s “Gordian Knot”.  He described the difficulties he was having.  Timothy said that he would love to put a picture of the process on the website and asked for suggestions.

As I had already done two pictures before I read his post I decided to respond.  The work that I did on this is detailed in my post of 5 June 2015 entitled “How do you construct Haken’s Gordian Knot?”.

My response duly appeared on the MathOverflow website in early 2015, but within a day or two it had been taken down and a notice appeared stating that only mathematicians of a certain status should post on the site.

That’s fine as my only maths qualification is General Certificate of Education at school.  At Harrogate Technical College I was thrown out of Shorthand and, with only three months to go to GCE exams they put me in for Maths and Art.  I owe many thanks to the Shorthand teacher, who thought my only skill was picking locks when someone forgot their locker key.  Also I have never had any discussion face to face with a mathematician about my art or my maths.

Following this setback I decided to set it all down in my Blog, in the three posts up to 5 June 2015.

Although I have not actually talked directly to a mathematician, I did correspond with Robin Wilson and Fred Holroyd at the Open University in the mid 1970’s about my ideas on the Four Colour Map Theorem.  I set out my ideas briefly in my post of 18 August 2015 “Four Colour Theorem continuous line overdraw”.

When Fred Holroyd responded to my write up, he used my own expressions and definitions which was very impressive.  He said that I had proved a connected problem, only proved in the world as recently as 16 years previously.   When I asked Robin Wilson about the announcement from a mathematician who said that he had proved the Four Colour Theorem, Robin said not to worry as he thought that this one was unlikely to be validated.  He said that he would prefer that my theory could be proved as it was elegant and also that they could use it.

The theorem was proven in 1976 by Kenneth Appel and Wolfgang Haken, involving running one of the biggest computers for over 1000 hours.  After this I decided to go onto other things, leaving my art and maths behind for almost 40 years.

Yes, its the very same Wolfgang Haken, who devised the Gordian Knot!

Ok, lets move on.  In February 2016 I received an e-mail from Noboru Ito, a mathematician in Japan, saying that he had read my article of 5 June 2015 “How do you construct Haken’s Gordian Knot?” and it was very helpful.  He would like to add it to the reference of his new book “Knot Projections”.

Of course I agreed and he later confirmed that he had referenced my work to the preface of his book.

Here is a picture of my copy of his book which was published in December 2016.

“Knot Projections” by Noboru Ito, published December 2016 by CRC Press, a Chapman & Hall Book.

Additionally, in November 2017 I received an e-mail from Tomasz Mrowka, a mathematician at the Massachusetts Institute of Technology.  He said that he was interested in acquiring a copy of my Twisting, Overlapping colouring of Haken’s unknot.  “It’s really quite striking and I would love to hang it in my office”.

I was delighted to send him a photo which he could enlarge and frame.

# Haken’s Gordian Knot and the Twisting, Overlapping, Envelope Elephant.

I constantly look for Continuous Lines in many fields of art, history, mathematics – anywhere, as I just do not know where they are going to crop up.  Currently I am casting an eye on Islamic Art and Celtic art and am developing ideas on those.

Recently I glanced through a book called “Professor Stewart’s Cabinet of Mathematical Curiosities” and came across Haken’s Gordian Knot, a really complicated looking knot which is really an unknot in disguise – a simple circle of string (ends glued together) making a closed line. Here it is.

Haken’s Gordian Knot, from Ian Agol. A simple circle of string (an Unknot) formed into a complicated continuous line.

When I looked at the Knot, it reminded me of my “Twisting, Overlapping, Envelope Elephant” continuous line in that it has a lot of twists. I realised straight away that a narrow loop on the outside (left lower) seemed to lead into the structure with its two strands twisting as it went, each time in a clockwise direction.  I followed the two twisting lines throughout the drawing until they ended in a loop on the outside (left higher).

I wanted to draw and paint this knot. My first drawing was of the line on its own. The depth of some of the lines reminded me of one of my earliest paintings “Leeds Inner Ring Road Starts Here”, which was based upon a sign board which appeared near Miles Bookshop in 1967 informing us of the route the new road would carve through the City. This was several years before Spagetti Junction was built near Birmingham. My picture had lines swirling all over at various heights in one continuous line.

Leeds Inner Ring Road Starts Here. Use of varying thickness of single continuous line drawing, overs and unders. Pre dates Spagetty Junction near Birmingham. Mick Burton, 1967.

My first picture of the Gordian Knot, in black and white, concentrated on the heights of the lines following the overs and unders shown by Haken.

Depth of lines in black and white, in Haken’s Gordian Knot. Mick Burton, single continuous line drawing.

But my main aim now was to use blue and red to show the twisting nature of the pair of lines running between the starting loop and the end loop.  This was intended to allow the viewer to more easily follow the loop and the twists throughout the structure.

Twisting, overlapping colouring of Haken’s Gordian Knot. Mick Burton single continuous line drawing.

Just like viewing my “Twisting, Overlapping, Envelope Elephant”, from my previous post, imagine that you have a strip of plastic which is blue on the front and when you twist it over it is painted red on the back.  Where blues cross each other you have darker blues, and correspondingly with reds.  Where blue crosses red you have violet.  I show the strips feeding through each other, like ghosts through a wall.  There are some darks and lights in there as well.  Most usefully, the background shines through to help make the strips stand out.

You can now get more of a feel for what is going on.  I counted 35 clockwise twists and two anti-clockwise (numbers 19 and 26).  Continued twists in the same direction tie in the ongoing loop, when it feeds through the two strands of its earlier route at least 12 times.

This is a preparatory painting, in acrylic but on two sheets of copy paper sellotaped together.  When I exhibit these pictures they will be hung as portrait, rather than the landscape shown here for comparison with Haken (as you will note from where my signature is).  I think they look a bit like the head of the Queen in portrait mode !

Having got this far, I realised that I should find out more about the Haken knot (or unknot), beyond Professor Stewart’s brief introduction.  How did Haken construct the knot and why?

Please see my next post, on this continuous line blog, to see how I got on.

# Continuous Lines in Escher Islamic Mosaic painting, STAGE 1.

Escher painting 1922 of Islamic Mosaic tile at the Alhambra. WikiArt. Continuous line study by Mick Burton.

I look for continuous lines in all forms of art.  I first saw this design in my daughter Kate’s book “Escher, The Complete Graphic Work”, by J.L. Locher.   We are both long term admirers of this artist.  Escher did this detailed painting  in 1922 when in Granada at the Alhambra, and its quality really hit me.  It was of an Islamic mural Mosaic tile,  which was made up of those geometric lines which are often seen in Islamic art, and I assessed it for continuous lines.

I could see that the overall symmetrical  pattern and I saw that Escher had painted the design BORDER, which seemed to indicate what happened to the lines after they hit the sides of the square.  I then worked out, from the Border Pattern, that the lines were fed back in the same routes on all four sides of the square.  From the point of view of finding a single continuous line, in my experience, such overall symmetry of the structure meant that it was very unlikely that there was only one line.

Here is the basic structure which I arrived at, which shows the “wiring” connections indicated by the border.  Let’s see how many continuous lines there are.

Escher Islamic Tile. Basic line structure, with border connections. Mick Burton continuous line study.

When I traced over the lines I found that there were in fact two continuous lines making up the whole design.  Here are the two results, a Main continuous line (in red) and a Minor one (blue).

Main continuous line, one of two. Escher Islamic tile design. Mick Burton continuous line study.

Minor continuous line, 2nd of two. Escher Islamic tile design. Mick Burton continuous line study.

By experimenting with border changes, a bit like swapping wiring connections, I did come up with a single continuous line, but the borders were no longer symmetrical.  It seems likely that the artist realised that two continuous lines was the best he could hope for whilst retaining overall symmetry.   In a LATER POST I will show how a border can be “tweaked” by a slight alteration to make one continuous line in the mural mosaic, and how this answer is achieved.  I will also show how the artist is likely to have worked out how to achieve two continuous lines by connecting up the correct loose ends.

I now needed to know  “How important continuous lines were, within this design, to the artist?”   It could be that Continuous Lines were incidental to other aims, or they may have been of prime importance.

In my NEXT POST I will apply my Alternate Overdraw technique to produce a Template of closed lines, which I use to decide upon the colours to allocate.   I will also suggest what the artist’s ideas were for the design and his colour selection.  In a FURTHER POST you will see how my colour allocation compares with the original colours and to what extent I feel that my ideas were the same or similar to those used by the artist.

All this has been done without any reference to the construction of the original line structure.  I have taken the completed structure as a starting point to apply my ideas.  I did not research in any detail on Islamic line construction, until after my whole study was completed.

I have recently found YouTube demonstrations by Eric Broug entitled “How to Draw a Mamluk Quran Page” and “How Grids and Patterns Work Together”, which gave me a good insight into pattern construction and include an explanation of a larger tile containing this Escher Mosaic design as a section.  This is a fascinating process used by the Islamic artists over 500 years ago.  Otherwise, I have not found any reference to borders, colouring, or specific meaning of this design.

Possibly my ideas will generate a new view on aspects of the creation of this and other Islamic designs.

Mick Burton, Continuous Line Blog. Continue reading

# Colour Sequence on Continuous Line Drawing

Fig 1. Completed Colour Sequence on Single Continuous Line Drawing of horse. Mick Burton, Continuous Line Blog.

How do I apply Colour Sequence to my Continuous Line Drawings, which I first developed in the late 1960,s ?  In my last blog post, about Alternate Overdraw of My Continuous Lines, I pointed out that Colour Sequence was the next stage and so here we go.  I will now show the stages involved in completing the colouring of this Horse.

Fig 2. Alternate Overdraw on Single Continuous Line Drawing of the Horse, as the first stage of Colour Sequence. Mick Burton, Continuous Line Blog.

From the two Alternate Overdraw examples in the previous post, I have chosen Fig 2 commencing at point “X” for this example (either “A” or “X” would result in the same colour sequence).

We are going to number all areas of the drawing, commencing with the background which will be numbered “0”.  In this example the background will remain uncoloured but “0” will also occur within the drawing and have a colour.

Fig 3. Initial numbering (0 and 1) of channels between Alternate Overdraws on the Continuous Line Horse.

You will notice that between all the closed lines, formed by the Alternate Overdraws, there are channels of areas.  These can be completely numbered alternately by only two numbers, which in this case are 0 and 1.  So, starting with 0 on the background, work through all these linked channels, see Fig 3.  This also sets the direction of the number sequence throughout the drawing.

Fig 4. Colour Sequence numbers 2 and 3 on the Continuous Line Horse.

The numbering progresses both upwards through positive numbers and downwards through negative numbers.  We will start with the positive direction and allocate the next pair of numbers, 2 and 3.  By moving from an 0 area into a 1 area, and on through its Alternate Overdraw border, we will enter an un-allocated area we can mark 2.  Now deal with all the other areas in this new channel, marking alternate areas 3 and 2, to complete this allocation.  After this we need to check for any further Alternate Overdraw channel, or channels, at this level adjacent to 1 areas and then allocate 2 and 3 to them also, see Fig 4.

We then need to check for any further Alternate Overdraw channels enclosed within any of the 2 and 3 channels.  If we found one we would allocate 4 and 5 to the new channel or channels.  In this case there is no higher level channel.

Fig 5. Colour Sequence numbers (-)1 and (-)2 on the Single Continuous Line Horse. Mick Burton, Continuous Line Blog.

Having  completed the numbering of areas in the positive direction, we now go into the negative in Fig 5.  By looking at an area 1 and moving through a 0 area with an Alternate Overdraw border we can cross through that into a (-)1 and (-)2 channel.  Mark the initial one (-)1 and then allocate alternately through the channel with (-)2 and (-)1.  After completing that channel, look for other un-allocated channels adjacent to 0 areas and allocate (-)1 and (-)2 to them.  Now look for further channels in the negative direction enclosed within a (-)1 and (-)2 channel.  There is one such, a single area (enclosed by its own Overdraw) in the front leg of the horse, which I have left blank in Fig 5 , which will be (-)3.

Fig 6. Colour Sequence colour chart for Continuous Line Horse. Mick Burton, Continuous Line Blog.

I was inspired by Rainbows in deciding on the sort of Colour Sequences I wanted to use for my Continuous Lines.  For shorter sequences, I settled for “partial rainbows” involving two prime colours only with a progression of colour mix and tones from light to dark.  For the Elephant I used yellows, greens and blues and for the Horse it was yellows, orange, red and browns in Fig 6.

I have carefully selected colours which have a stepped progression, both in colour and tone, and where possible I apply them from the tube (poster colour in the late 1960’s or acrylic now) to achieve an even and solid result.  I avoid mixing if I can, to retain the pure consistency of colour application across the painting, but sometimes it is necessary.

Fig 7. Black and white photocopy of Colour Chart for Continuous Line Horse.

To assess the accuracy of the progression steps of my Colour Sequence chart, I do a black and white (or grayscale) photocopy of my chart to check that the steps still work in monochrome, see Fig 7.

Having produced the Colour Sequence chart, we need to decide the direction of the colours matched to the numbers, ie. Light to dark in an upward or a downward direction.  Generally I see whether a scale would mostly coincide with where a natural highlight would be, or have more darks towards the lower parts in a drawing to infer shadow.  Usually it is fairly obvious, but you can always start again with the other direction of colours.  Note that my style may take advantage of natural hints of highlight or shadow on a subject, but generally these aspects (along with perspective) are absent.

I remember that when doing equations at school, which produced two answers (+ or (-) ), was a puzzle to me which no one could explain.  I understand the concept of a practical outcome from having two answers a bit better now.

Fig 8. Initial Colour Sequence pair of colours on Continuous Line Horse. Mick Burton, Continuous Line Blog.

Once we have decided on the colour match with the numbers, the initial two colours can be painted in, ie.  Vermillion = 0 and Orange = 1, see Fig 8.

Fig 9. Second Colour Sequence pair of colours on Continuous Line Horse.

We can then match numbers 2 and 3 in areas to the colours required in the next channels up, or simply apply Golden Yellow to areas across the overdraw from Orange and then its alternate colour Permanent Yellow, in Fig 9.

Fig 10. Third Colour Sequence pair of colours, in the negative direction, on the Single Continuous Line  Drawing of Horse. Mick Burton, Continuous Line Blog.

Now we can match numbers (-)1 and (-)2 in the negative direction, or simply apply Light Brown to areas across the Overdraws from Vermillion.  When these Light Brown and Burnt Sienna channels have been completed the last channel colour is (-)3 which is Burnt Umber.  In Fig 10 I have left this final area blank  (on the front left leg of the Horse).

So you have seen my Colour Sequence method, using Alternate Overdraw, for Continuous Line Drawings.  Sorry if it has been a long explanation (particularly if you grasped it quickly or had already come across parts of it), but I have tried to pitch it as helpfully as I can, based on my demonstration sessions.

A couple a years after I started Colour Sequence I came across the Winding Number Theory.  There is a connection and I did pick up one or two ideas from it.  I will talk about this in a later post, but as always I am not a trained mathematician and so I will keep talking in pictures.

I hope that you will give it a try and I am sure you will enjoy the ride, as I have for so long.

If you display or publish your results, it would be great if you could specifically acknowledge me and my ideas.

# Alternate Overdraw on Continuous Line Drawing

After my early attempts at continuous line drawing, and then alternate shading, I tried Alternate Overdraw on top of my continuous line drawings.  This produced some fascinating results which led to developments throughout my art.

Draw from A to B to start Alternate Overdraw on Single Continuous Line Drawing of the Horse.

Lets use the Horse as an example.  Here is a lightly drawn Continuous Line (sorry if you have to tilt your lap top to see it all).  Start at point A and use a thicker pen or marker and draw over the first section of line, in the direction of the arrow, between the two crossovers.  Then miss a section before overdrawing the next section of line.  Keep going overdrawing alternate sections to point B.  You will see that already some overdraw sections are forming closed lines.

Complete Alternate Overdraw of Continuous Line Drawing of horse from point A.

The next illustration shows the complete Alternate Overdraw and all these new darker lines form closed lines.

Naturally, if we start the Alternate Overdraw in a section which was not overdrawn in the above example (eg at X below), then this produces a result where a completely different set of closed lines appear.

Other Alternate Overdraw on Single Continuous Line Drawing of horse, starting at X.

From the above findings I first developed my Colour Sequence ideas, which I will expand upon in the next post.

Later I used the closed lines to help in the construction of large models of my continuous line drawings as well as to devise hidden drawings within continuous lines.  More later on those.

The Alternate Overdraw method also led to a way to find a path through Four Colour Theory maps as part of my attempt to prove that theory nearly 40 years ago.

So, watch this space !!

# Variable grid single lines

In 1969 when I was selling prints in the Merrion Centre art exhibition in Leeds, some one asked “Are your drawings done by computer ? ”   At the time computers were rubbish regarding any form of drawing, so I eventually made my own “drawing machine”.

In 1973 I built a box with 8 perspex rulers lying in one direction and 8 more perspex rulers lying on top at 90 degrees to the lower ones.  Each ruler had alternate inches marked (or not marked)  with a thickish black line.  Any ruler could be pushed in or out one inch to change the whole pattern of single lines displayed by looking down through the rulers (the box could be lit from underneath).

I could keep altering various rulers until an interesting pattern of lines appeared.  I call these “variable grid single lines”.  One seemed to represent a church and I applied a colour sequence to the picture.  Recently I have modified some of the sky colours and stretched the picture to a rectangle on canvas and here is the result.

Church with Red Sky. Variable grid single continuous line drawing. Mick Burton, 2014

I did many larger drawings on large square graph paper but found that you can’t vary the lines without a lot of rubbing out.  What you can do is look for smaller areas within the grid which provides a good picture in its own right and replicate that.  The single lines can go out at the sides of the picture, but it is possible to create a continuous line within the picture and then any lines within that are all closed lines as well.

Both these methods are,  of course, stepping off points for putting these sorts of designs onto a modern computer and generating loads of possibilities in the twinkle of an eye.  I try not to cross that line and feel that it is important for me to keep in the pre-computer art sphere, so that any of my drawings can be created using the mind and the hand with minimal use of technology.   Some latitude is allowed, for as  David Hockney has said, “a pencil is technology”.

I am interested in what computers produce, even though I do not want to use their creative expertise myself,  and was amused when I read about an artist who programmed his computer to generate hundreds of his pictures overnight, whilst he was asleep, and then in the morning he would wade through the results and pick out a few good ones.

The brick wall, as far as my interest in computer pictures or animation is concerned, is when I cannot tell whether what I am seeing is a photograph or film sequence of the real world or a clever computer animation.  That is where art dies.