Nonograms are picture logic puzzles where the goal is to draw cells based on the number hints. Each row and column must have filled-in cells according to the numbers to the left or the top, where each number refers to subsequent colored cells, and all of these sets are separated by at least one empty cell.
Write 'd' to draw a cell, and 'x' to mark a cell as empty.
You are allowed to make 3 mistakes before the quiz ends
If you are new to nonograms, check out a guide or the Wikipedia article
100% and no mistake for me.