Skyscrapers (BrainBashers)

Skyscrapers turns a Latin square into a city skyline. In a 6x6 puzzle every row and column holds the heights 1 to 6 once each. The numbers around the border are lookouts: each tells you how many buildings you can see looking along that row or column from that side. A tall building hides every shorter one behind it, so a clue of 1 means the tallest building stands right at the edge, and a clue equal to the grid size means the heights rise one by one.

BrainBashers, Kevin Stone's puzzle site, posts a 4x4 grid at Easy/Medium and Hard each day, then 5x5, 6x6, 7x7 and 8x8 grids at Easy, Medium and Hard, with a 9x9 weekly special. Some grids give a digit or two to start. Each puzzle has its own dated page with check, pencil marks, answer, print and restart buttons, an option to show mistakes when checking and an optional clock. The help page has a walkthrough.

Puzzles change at midnight GMT or at your chosen time zone, and the last four weeks stay in the date list. Random easy, medium and hard buttons give extra grids beyond the daily set. We saw no adverts on the puzzle pages, and no account is needed.

It suits sudoku players who want clues that need a little spatial thinking, and the small grids make a quick start.

On a phone the grids are drawn at a fixed size: at 430 px wide even the 6x6 clips the clue column on the right, and the 8x8 runs past the edge, so a larger screen or landscape view helps.