In honor of tau day (a math holiday celebrated on June 28 every year), I have written some exercises at wikiproofs.org tau day. If you have a little time to go to that page and try to go through the exercises, I'd appreciate your feedback on writing style, whether they are too easy or too hard, whether they were too long or too short, and any other suggestions. I'm hoping this will be a fun game/exercise for anyone interested in math but I am trying to make it accessible to someone with no experience in formal proofs.
If you are here to read about programming, I intend to keep writing about that too, but the math proofs have been a good part of my hobby activities lately. It is kind of like programming anyway (processed by a computer, needs to follow pretty specific rules to work, can be addictive in some of the same ways).