[jgrahamc]

I had not thought about it that way and to be clear some of the parameters (such as the sizes you mention and also the row numbers in ELEMENTS) were found by a bit of experimentation. With the fundamental algorithm in place there was a bit of iteration to get something that looks good on screen (almost all the time).

The other thing was the title. The code originally could have had two letters (e.g. P and E in APERIODIC) joined at a vertex and it looked odd (it looked like the word was broken) so there's specific code to make sure that doesn't happen.