Singles

Singles presents you with a grid filled with white squares, all of which contain numbers—some repeated, some unique. Your goal is simple in concept but nuanced in execution: eliminate duplicates so that every number appears exactly once in the final grid.

Your task is to colour some of the squares black (removing the number) so as to satisfy all of the following conditions:

• No number occurs more than once in any row or column.
• No black square is horizontally or vertically adjacent to any other black square.
• The remaining white squares must all form one contiguous region (connected by edges, not just touching at corners).

To achieve this, you black out (i.e., remove) the correct instances of repeated numbers, leaving behind only one occurrence of each. The twist? You’re not told which copies to keep—you must deduce it through logic. The key constraint is that no two remaining (unblacked) numbers may be adjacent, not even diagonally. This “no-touching” rule forces careful spatial reasoning: keeping a number in one cell may block its neighbors from containing any other number, thereby influencing which duplicates must be removed elsewhere.

The puzzle is always uniquely solvable through pure deduction—no guessing required.

Left-clicking an empty square will color it black; left-clicking again will restore the number. Right-clicking will add a circle (useful for marking a cell that is definitely not black). Clicking outside the grid toggles whether black squares completely hide their numbers or display them in dark gray.

You can also use the arrow keys to navigate the grid. Pressing Enter or Space will toggle the current square: Enter blacks it out, and Space adds a circle. Pressing the same key again will revert the action—restoring the number or removing the circle.