Pi Sudoku is originally created for Pi Day (March 14 = 3.14).
Math geeks all over the world celebrate their math-geekiness on this day with pie-eating contests, recitations of the digits of pi, and occasionally fundraisers where math faculty get hit in the face with pies.
Rules: Fill in the grid so that each row, column, and jigsaw region contains 1-9 exactly once and ? three times. Happy Puzzling!