Watch the swinging droplet. Tap the action button or Space when it overlaps the moth. Choose a short or long silk line with the line-length control or left/right arrows.
Touch and keyboard supported · Gameplay stays ad-free
By Rafael, WebTug creator · Updated September 7, 2026 · Source-linked learning
What the game helps you notice
A bolas spider flicks a silk line with an adhesive droplet toward prey. This timing game uses an ideal pendulum: line length affects its period, while the sticky tip provides the contact point.
What does a longer pendulum line change?
Its natural swing takes longer: in the small-angle model, period is proportional to the square root of line length.
A game inspired by science—not a biological simulator.
The repeating swing and prescribed moth path are practice patterns. Real strikes are actively driven, and stretching silk and deforming glue are more complex than a rigid pendulum.
Try this experiment: Which line takes longer to swing?
Keep swing energy and swing loss unchanged. Compare a short line and a long line, and count swings over the same interval.