Goal: Place exactly one number in each outlined region. The number equals the region's size (cell count).
Rules:
1. Each region gets exactly one number = its size
2. No number may repeat in any row or column
3. Numbered cells cannot touch orthogonally (up/down/left/right)
4. Cross (X) cells cannot contain numbers
5. Pre-filled numbers (givens) are fixed clues
Controls: Click a cell to place the region size. Click again to remove. Use Erase mode to clear cells. Press H for hint, Enter to check, R to restart.