Kepler’s New Year’s Gift — On the Six-Cornered Snowflake

Some things never change. In winter 1610, Johannes Kepler was stressing out about holiday gifts -- in particular, one for his friend and benefactor, the rather grandly-named Johannes Matthaeus Wacker von Wackenfels. Kepler, at the time employed as Imperial Mathematician at the court of Holy Roman Emperor Rudolph II, records his musings on the problem in the opening pages of his now-famous discourse, The Six-Cornered Snowflake.