Inverse Kinematics — FABRIK Chain Solver (2D)

This 2D companion runs the same algorithm as the 3D robotic-arm demo — FABRIK, Forward And Backward Reaching Inverse Kinematics — stripped down to a flat canvas so every joint move is visible at once. Drag the cyan target and a chain of 2 to 14 rigid links re-solves itself in real time using the genuine iterative forward/backward position-constraint passes, not a scripted animation. Adjust joint count, per-link length, convergence tolerance and the iteration cap, and watch the live counter report exactly how many passes the solver needed.