George Duke wrote on Wed, Jan 12, 2011 05:28 PM UTC:
Triggered by yesterday's five 'ones', what was happening fifteen years
ago to the month? 50 years ago to the year, and 500 years ago to the
decade?
15 years ago here: Avalanche Chess posted of Betza 1970s device,
http://www.chessvariants.org/mvopponent.dir/avalanche.html.
50 years ago: Ultima invented, http://www.chessvariants.org/other.dir/ultima.html, posted 15 years ago, a perfect 15/50.
60 years ago: Thomas Rayner Dawson dies age 62,
http://en.wikipedia.org/wiki/Thomas_Rayner_Dawson.
500 years ago: Lucena's takes root,
http://en.wikipedia.org/wiki/Luis_Ramirez_de_Lucena.