Magic Squares
A nine-by-nine number puzzle with five difficulty tiers, pencil notes and undo. It needs JavaScript to play.
Magic squares came first: number grids built so that each row, column and diagonal adds to the same total. They were studied as mathematics for centuries and carried occult or mythical meaning in some traditions. In the late 1800s French newspapers began turning partly filled magic-square-style grids into puzzles; the modern version later took off in Japan as Sudoku.
The rest of Symbol Mirror is free timing and card tools: Calendar, Cycles, Card + Card and Names.