Put Theory Into Practice
One Stroke generates infinite puzzles based on these mathematical principles. Every puzzle is guaranteed solvable — test your graph theory knowledge in real time.
From 18th-century bridges to your iPhone — explore the graph theory that powers every puzzle
One-stroke puzzles aren't just games — they're rooted in a branch of mathematics called graph theory, pioneered by Leonhard Euler in 1736. Understanding the theory can help you solve puzzles faster and appreciate the elegance behind them.
The puzzle that started it all. In 1736, Euler proved why you can't cross all seven bridges of Königsberg exactly once — and invented graph theory in the process.
Core ConceptThe mathematical foundation of every one-stroke puzzle. Learn what makes a graph traceable in one stroke and why some shapes are impossible.
StrategyThe single most useful rule for solving one-stroke puzzles. Count the odd-degree vertices and you'll know instantly if a puzzle is solvable — and where to start.
ShapesTriangle, square, star, house, envelope, and more. A template-driven hub for common shape queries.
One Stroke generates infinite puzzles based on these mathematical principles. Every puzzle is guaranteed solvable — test your graph theory knowledge in real time.
Infinite puzzles. Adaptive difficulty. No forced ads.