The Santa Claus puzzle is a classic concurrency problem: Santa sleeps until awakened by either all 9 reindeer or 3 of 10 elves. He performs indivisible actions: harness reindeer to deliver toys then unharnessreindeer who vacation, OR consult elves on toy R&D then show them out to resume work. Key constraint: waiting reindeer must be served before waiting elves. The puzzle explores synchronization primitives and priorities in concurrent systems. Model checking can verify correctness of solutions by exhaustively exploring state spaces for deadlocks and priority violations.