Labs · prototype
Echo
A few cells are already labeled ● or ○ by a hidden rule. Figure out the rule, then label every remaining cell. Tap a cell to cycle ○ → ● → blank. Stuck? Reveal a cell's true label for a point penalty. Hit Check when you think the whole grid is right.
0 reveals used
Legend: lilac = given, peach = revealed, white = your call. Cycle blank → ○ → ● by tapping.