2021-10-06 Thanks to Toombler, Andrea Gilbert (Clickmazes), Jack Lance, Portponky for feedback, in particular about the rectangle input drawing mode, and to Karoo, dohz for finding a non-uniqueness in one of the puzzles. 2024-02-25Eli Doris (TwoHoleStraw) brought the rule panels into the modern format - thank you! Minor style tweaks.