Nonogram

A Nonogram — you may know it as Picross or Griddlers — is a picture hiding inside a grid of numbers, waiting to be reasoned out. The clues running along each row and column list the runs of filled cells in order, so "3 1" means a block of three, a gap, then a single, and your job is to fill exactly the right cells until the picture emerges. Crucially, it is a game of deduction, not guessing, and the way in is to start from the biggest clues — in a ten-wide row a clue of eight barely fits, forcing several cells no matter how it slides, and those forced cells are your first solid ground. From there it becomes a conversation between rows and columns: a cell you fill from a row clue can unlock a column, which unlocks another row, and marking cells you know are empty with an X is every bit as powerful as filling them in. Look for overlaps where a long run must cover the same squares wherever it sits, and never guess while a certain move exists. Free, with Easy and hard sizes and your best time per size kept.