This free app is a game that lets you play a new form of the classic logic puzzle called a nonogram. A nonogram is a picture that has numbers hidden in it. In this case, the hidden numbers are in the form of discrete tomography that measures how many unbroken lines of filled-in squares there are in any given row or column. To solve a puzzle, you need to determine which cells will be boxes and which will be empty.

The first step in the solving process is to find out which cells are to be left empty (called spaces). The second step is to determine which boxes are to be filled (called boxes). The third step is to find out how many empty boxes there are in the row or column.

It is very important to find out the number of spaces and boxes because later in the solving process, these spaces and boxes help you determine where a clue (continuing block of boxes and a number in the legend) may spread.