Skyscrapers

Overview

Skyscrapers places building heights in a Latin square. A board of size five uses heights one through five once in each row and column. Clues outside the grid describe how many buildings are visible from that side when taller buildings hide shorter ones behind them. The clue counts visible buildings, not the sum of their heights. There are no Sudoku sub-boxes. Opposite clues can constrain the same row in very different ways, while column uniqueness limits the candidate heights for each position. SonoTap hosts the Towers implementation with generated puzzles and selectable sizes. Its compact notation lets you reason about a city's skyline without handling moving pieces, and pencil marks help retain candidate heights during a longer deduction.

How to Play

Select a square and type a height or press its on-screen number. Move the selection with the keyboard or arrow buttons, and use Backspace to remove an entry. Secondary-select a square before entering pencil candidates if you want to record possibilities rather than a final height. Read each edge clue from its own direction: a left clue scans left to right, while a bottom clue scans upward. Fill the grid without repeated heights in any row or column and with every supplied skyline count correct.

Tips & Strategy

A visibility clue of one forces the tallest building into the first square seen from that side. A clue equal to the board size forces strictly increasing heights across the entire line. Use those placements to eliminate heights from intersecting rows and columns. For intermediate clues, consider where the tallest building can stand, since nothing behind it is visible. Avoid confusing visibility with the number of height changes: a short building after a tall one remains hidden even if it is taller than the building immediately before it. Pencil only the candidates supported by both perpendicular lines.

About this version

Skyscrapers uses the locally compiled towers engine from Simon Tatham’s Portable Puzzle Collection. The original authors retain credit under the MIT license. SonoTap provides the browser adaptation and this guide.