21 Cards

This puzzle drops you into a 3x7 board holding the numbers 1 through 21, scrambled at the start. Your goal is to put them back in perfect order, from the smallest value in the top-left corner to the largest in the bottom-right. The catch is that you can only move tiles by swapping them with a neighbor—either side-by-side or stacked directly above or below. There are no timers, no score multipliers, just pure spatial logic and careful planning. Each swap nudges you closer to the solution, but a single wrong move can send you on a lengthy detour. The grid size keeps things manageable, yet the number of possible arrangements makes every playthrough a fresh challenge. It's a quiet, focused exercise for your brain, ideal for short sessions or longer stretches of concentration. Success feels earned, and the satisfaction of seeing that final ordered lineup is well worth the effort.