Steering Law: Tunnel Task Simulator

Every UI element you slide a cursor through — a scrollbar track, a nested drag-menu, a stylus gesture channel — obeys the steering law, not Fitts's Law: difficulty accumulates continuously along the path instead of resting on one target's size and distance. This simulator renders a real 3D winding corridor whose width and curvature you control, lets you steer a puck through it with the pointer, and integrates the corridor's true Index of Difficulty (ID = ∫ ds/W(s)) from its exact geometry. A run only counts if the puck stays inside the walls from the green start gate to the red finish gate; your measured movement time is then compared live against the steering-law model's prediction (MT = a + b·ID) and converted into a throughput figure in bits per second, the same metric HCI researchers use to benchmark pointing devices.