Try One Stroke Free on iPhone
Infinite puzzles. Adaptive difficulty. No forced ads.
A simple triangle is one of the easiest shapes to analyze with the odd/even vertex rule.
Can it be drawn in one stroke? Yes. A plain triangle has zero odd vertices, so it has an Euler circuit.
Where should you start? On any corner if the triangle is plain and closed.
Common mistake: Mixing up a plain triangle with a triangle that has extra internal lines, which changes the vertex count.
Infinite puzzles. Adaptive difficulty. No forced ads.