Picture a tiny city and stand at the edge of one street. How many rooftops can you see? Skyscraper Sightlines unblocked turns that question into a number puzzle, with clues around the border telling you how many towers are visible from each spot.
Simon Tatham created it under the name Towers for his free puzzle collection, and here it is drawn with little 3D buildings. Every board has exactly one answer you can reach with logic alone.
How to play Skyscraper Sightlines
On a 5 by 5 board, towers are 1 to 5 tall. Each row and each column must contain every height exactly once, so no height repeats in a line.
Border clues count what you would see looking into that line from outside. A tall tower hides every shorter one behind it. For example, the row 1, 3, 2, 5, 4 shows three towers from the left (1, 3 and 5) and two from the right (4 and 5).
Choose a square and enter a number to put up a tower there. When you are unsure, jot tiny pencil notes for the candidates instead. Repeats and broken clues turn red, and the grid flashes once everything is correct. The Type menu has several sizes and four difficulty levels.
Controls
| To… | Keyboard | Mouse | Touch |
|---|---|---|---|
| Build a tower | Arrow keys to pick a square, then type its height | Click a square, then type a digit | Tap a square, then tap a digit button |
| Add or remove a pencil mark | Enter switches the cursor to pencil mode, then type a digit | Right-click a square, then type a digit | Set Tap to Pencil mark (or press and hold a square), then tap a digit |
| Clear a square | Space, Backspace or 0 | — | Tap the square, then Clear |
| Fill every empty square with all pencil marks | M | — | — |
| Grey out a clue you have finished with | — | Click the clue | Tap the clue |
| New game, undo, redo | N, U, R | Menu buttons above the grid | Menu buttons above the grid |
Tips
- Clue 1 means the tallest is right there. The square next to a 1 always holds the maximum height.
- A full-size clue solves the line. If a clue equals the grid size, the line climbs 1, 2, 3 and so on, starting from that clue.
- Cap the first square. A big clue means the tower beside it must be short. On a 5 by 5 grid, a clue of 3 caps that first tower at 3.
- Fill pencil marks fast. Press M to put every possible height in every empty square, then erase as you rule them out.
- Grey out used clues. Click a clue once its line is done so your eyes skip it.
Skyscraper Sightlines questions
Why are some towers already built at the start?
On harder settings and larger grids, the game may place a few fixed towers and leave some clues blank. The puzzle still has just one solution.
Can I turn off the 3D look?
Yes. Under Game, then Preferences, choose the flat 2D style. Heights then appear as plain numbers.
How do pencil marks work on a touchscreen?
Switch the bar under the grid to pencil mode, or press and hold a square, then tap the digits you want to note.
