The butterfly looks even. One cut and a brass scale will tell you how close you came. A free browser puzzle from Sjouheim, with more shapes and daily puzzles in Slicewise on Android.
Drag one line through the paper butterfly, or tap two points to set the cut. Watch both halves land on the scale and see how close you got to 50/50.
Slicewise: One-Cut Butterfly Challenge was submitted to SlowDen by Sjouheim. SlowDen did not make this game - it is published here from the developer's own submission, added on 2026-11-09. It runs in the browser with no download, no install and no sign-up.