The “case study?” column was the whole point of the spreadsheet — identifying which projects I still needed to write up for my portfolio — but at this point I looked at the sheet, and thought “This is honestly a better overview of the work I do than any ‘portfolio’ I’ve seen”.
So I tweeted a screenshot, joking/trolling that it WAS my portfolio (I didn’t include any winks or notes that I was still planning a “real” portfolio), but people didn’t respond with the lulz I expected — they got the idea, or took it at face value and said they were going to do their portfolio this way too!
Today I made an Exit page. So many people end their visit by hitting the Back button on their browser. The exit page is a last attempt to get them to explore the Blog Directory to find an entertaining blog. Or failing that to try a search on a search engine they may have never tried before.
An audacious attempt to reshape blogging, to see where it can go next!
Podcasts and video have really taken over - to the extent that it feels like reading may be falling behind. Can we enhance text and imagery on the Web? Try to give blogging new life?
Wang tiles (Hao Wang, 1961) are a class of formal systems. They are modelled visually by square tiles with a color on each side. A set of such tiles is selected, and copies of the tiles are arranged side by side with matching colors, without rotating or reflecting them.
The basic question about a set of Wang tiles is whether it can tile the plane or not, i.e., whether an entire infinite plane can be filled this way. The next question is whether this can be done in a periodic pattern.
In 1966, Wang's student Robert Berger solved the problem in the negative. He proved that no algorithm for the problem can exist, by showing how to translate any Turing machine into a set of Wang tiles that tiles the plane if and only if the Turing machine does not halt. The undecidability of the halting problem then implies the undecidability of Wang's tiling problem.