In a room almost at the diagonally opposite corner of the building another “painting” had caught my attention. It is in fact a lithograph.The building indeed had a square plan. With a quadrangle in the middle. A corridor ran parallel to the sides of the square and had rooms on either side of it. All the rooms had windows either facing the quadrangle or the world outside. In this case it was a print. I wanted to go in and take a look but the room was empty whenever I passed by.
One afternoon I found one of the two people who shared the room in and sought his permission to walk in and look at the print. There were other interesting prints hanging on the wall but this one was special. I had a good look at it.
The occupant asked me why I was so interested. I told him that I was always interested in Escher's works and that this one was really special. He asked me why. I told him the story.
This was a print of Escher's work called the Print Gallery. Like most of Escher's works, this one too was art and mathematics and optical illusion all combined. It shows a man viewing a print hanging on the wall of the gallery. As you proceed, visually, along the path he is likely to follow, you can see other prints. As you do so, the inside of the gallery becomes the outside of the gallery and the outside in.
Since no such thing exists, and can ever exist, Escher must have painted it completely from imagination, seeing it through his mind’s eye. As the painting goes ahead it becomes so complicated that he did not know how to finish the painting! It stretched even his prodigious visualisation to its limits and beyond, because, he gave up. It was one of his unfinished works. And so it stayed.
Hendrik Lenstra, a professor of mathematics at the University of Leiden was travelling to the US. He holds a joint position in the University of Berkeley too. . He read about this work in an inflight magazine. He wondered if this problem could be reduced to a mathematical one, solve it using computers and finish the painting. Once he returned home, he gave this problem to a few of his colleagues doctoral students and that is exactly what one of them did!
I had read about this very recently and the colleague, who had read about it too, but in Nederlands, was happy that it was so well known! Later I had an opportunity to work with him and this incident, I felt, was one of the reasons that he was so friendly and helpful!