The puzzles are randomly generated, so you never play the same game twice. And all puzzles have a unique solution. You can quit a game at any time and continue later - the game state including undo/redo will be restored.

Features:

• 4 levels of difficulty.
• Save/Restore helps you to try alternative ways.
• Undo/Redo with virtually unlimited levels.
• Mark up candidate numbers, or
• enable automatic candidate list.
• Choose subscript or dot notation mark-up.
• Show conflicts.
• Highlight digits.
• Use your convenient way to enter digits:
  (1) multi-push, (2) number keys, or (3) menu driven.
• Portrait and landscape display.
• Best times table.