Enjoying the trip, day and night

I spent the day at the Gemeentemuseum library looking at materials from the archives. They say they have the world's largest collection of Escher's papers. I was able to see many very interesting items and took hundred of photos. There were many small patterns Escher produced using repeated rotated and reflected copies of simply decorated square tiles. I looked at details of Escher's trip to southern Spain, including pictures from the Alhambra in Granada and the Alcazar in Seville. While there were no photos from Cordoba, but there was a large charcoal drawing of the column forest in the Mezquita. There were interesting details from work Escher was commissioned to do. I saw several colored drawings Escher made of tiles in the Alhambra. I read letters to Escher from many people including H.M.S. Coxeter, Martin Gardner, and Donald Knuth. There are more items in their archives and also some in private collections. Overall a very productive and amazing day. All the staff were very helpful, particularly Vivian and Herbert.

Escher, Day and Night, 1938

Escher produced some amazing works. He was the first person to explore using uniform tessellations and use these as a design element in his works. For example, in Escher's Day and Night, the black and white birds face opposite directions. There are no gyration points, but translations in the horizontal direction for each colors, however one requires both a reflection and a translation to move a white bird to an adjacent black bird. This combination of a translation and reflection is called a glide reflection. This is yet another type of symmetry pattern.

After leaving the archives, we went to a small local market for some cold beverages and chocolate. We stopped at our hotel and then went local yarn shop. Amy enjoys going to new knitting shops where ever we travel. Amy purchased some interesting new yarn that she said was possibly going to be a gift for someone. We did a little window shopping and gift shopping. We then went to dinner at a pub and have some typical pub food and libations. We then walked back to our hotel, past quite a few coffee shops, and are planning for tomorrow. Interestingly, the police stopped to talk to a young man about jaywalking just as we were approaching the crossing. At least Amy and I know better than that!