This sort of reminds me of this neat day-looker-upper: https://imgur.com/KKipvmV https://imgur.com/KKipvmV . To find the day of the week of Month-Date, just fin

This sort of reminds me of this neat day-looker-upper: https://imgur.com/KKipvmV https://imgur.com/KKipvmV . To find the day of the week of Month-Date, just find their intersection in the table. Afaik this is the most compact representation of a year's calendar possible. You do need a new one each year, but there are only fourteen distinct possibilities (7 days that Jan 1 can be, times 2 choices of leap year or not). Figuring out the equivalence classes of years is a fun problem.