Forward planning
Skyline
The tower-rearrangement planning puzzle: recreate a target skyline by moving one floor at a time, scored against a mathematically-verified minimum move count. There is no clock: pausing to plan before your first move is the skill being measured, and moving too fast is exactly what the scoring penalises. A staple of trading-firm cognitive assessments.
Settings
SaveSession
10 levels with a known minimum from 2 up to 7 moves, and no clock anywhere: planning before the first move is the skill being measured, so take your time.
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Frequently asked questions
What is Skyline?
Skyline is the tower-rearrangement planning puzzle from trading-firm cognitive assessments, built on the research literature’s Tower of London task. A target arrangement of coloured floors is shown; you recreate it by moving one top floor at a time, scored on how close you land to the known minimum number of moves.
Why is there no timer?
Deliberately. This game measures planning: pausing to solve the level in your head before the first move is exactly the behaviour that predicts fewer moves, and a visible clock pushes people to start moving immediately. Take as long as you need before touching anything: the first-move pause is recorded as a feature, not a cost.
How is the minimum move count known?
Every level is generated by exhaustively searching the puzzle’s full state space from the start position, then choosing a goal at an exact distance. The minimum shown is mathematically true for that level, not an estimate, and every level is solvable by construction.
What's the difference between Open and Capped mode?
Open mode allows unlimited stack heights on all three towers: the forgiving configuration. Capped mode restricts the towers to 3, 2 and 1 floors (the classic research configuration), where the scarcity of legal moves makes genuine look-ahead unavoidable. Capped mode is available with a premium subscription.
What strategy works?
Work backwards from the target: identify which floor must be placed last, and which moves free it. Solve the complete sequence mentally before your first move: the measured pattern is that longer initial thinking time goes with fewer moves. Ball-sort puzzle apps are decent transfer practice for the Open configuration.