The board is a square grid of identical cells. Each cell holds a skyscraper: the larger the number, the taller the building.

• The number in a cell is the building height, from 1 to the board size.
• The numbers around the edge show how many buildings are visible from that side of the row or column.
• Every row and every column contains each height exactly once.

Tap an edge number to see how many buildings are visible from that side.