Frame (Mind Loft)

Frame is a sudoku with a border of clues. Outside each end of every row and column is a number: the sum of the first three squares reading inward from that edge. That makes thirty-six sums, all printed every day, alongside the usual rule that each row, column and 3x3 box holds 1 to 9 exactly once.

The reasoning is arithmetic on groups of three: a 6 can only be 1, 2 and 3 in some order, a 24 must be 7, 8 and 9, and the middle values are where most of the deduction happens. Selecting a square lights up the two sums that cover it. Every board has a single solution reachable by logic, and the border is always needed: the printed digits alone would allow more than one grid. Wrong entries are not flagged; a clean solve scores 10 and the leaderboard is decided on time.

Printed digits inside the grid fall through the week, from 14 on Monday to 4 on Saturday, and the Sunday Edition prints only two. Notes, Undo, Erase, Clear, auto-move and a hint are available, and a new board arrives every day at midnight Eastern.