Sudoku 4×4
Each row, column, and 2×2 box must contain 1–4 exactly once. Tap a cell, then a digit. Givens are fixed. The default board is the UTC daily puzzle (same calendar day everywhere); use New puzzle for a random one from the pool.
Each row, column, and 2×2 box must contain 1–4 exactly once. Tap a cell, then a digit. Givens are fixed. The default board is the UTC daily puzzle (same calendar day everywhere); use New puzzle for a random one from the pool.