Rules: Place a digit from 1 to 9 in each empty cell so that each digit appears exactly once in each row, column and 3x3 outlined box.
Clues outside the grid are skyscraper clues: Each digit in the grid is a "skyscraper" whose height is the digit in that cell. Taller or equally tall skyscrapers obscure the view of smaller or equally small ones. Numbers outside the grid indicate the number of skyscrapers that can be seen (along the indicated diagonal) from that vantage point.
