IBM Ponder This
Crack a new monthly puzzle that usually takes a program and a clever search to solve
Ponder This is a monthly puzzle from IBM Research in Israel, published every month since 1998. Each puzzle asks you to construct or find something specific, and most are designed so that you need to write a program, often a careful search or simulation, to get the answer. Many add a harder starred bonus.
Free · No login · Browser · Advanced
About IBM Ponder This
The October 2026 puzzle, for example, asks for a complete 81-move game of a variant of Ultimate Tic-Tac-Toe where the last nine moves each win a small board, with a 5-by-5 bonus version. It suits programmers who enjoy Project Euler style problems with a combinatorial twist.
There is no account: you email your answer, and correct solvers are listed by name on the puzzle page. The full archive of past puzzles and solutions is free to browse.
Made this game? Claim it →
Tips and discussion
No tips yet.
Sign in to share a tip.