Robot Arm Painting: Toolpath-Driven Brushstroke Generator

This simulator drives a real two-link SCARA-style painting robot with closed-form analytic inverse kinematics: pick a generative toolpath (a rose curve, a Lissajous figure, or an expanding spiral), and the arm's shoulder and elbow angles are solved geometrically every frame to keep the brush exactly on that curve. A pen drops from the wrist to a canvas below and deposits instanced paint dabs along the path, whose spacing and hue drift track the tool's real angular speed — the same closed-form 2-link IK used inside real SCARA pick-and-place and robotic-art rigs. Live readouts track both joint angles, instantaneous tool speed, and how much of the canvas has been painted.