Inside the cube are rapidly spinning flywheels driven by electric motors. When the wheel accelerates or decelerates, the cube experiences an equal and opposite torque due to conservation of angular momentum. By precisely controlling wheel speed in real time, the system can continuously shift its orientation and maintain balance on an edge or corner. The control problem is significantly harder than balancing a typical inverted pendulum because the cube has multiple unstable axes and nonlinear rotational dynamics. An onboard IMU (inertial measurement unit) measures angular velocity and tilt, while a feedback controller calculates how much torque each reaction wheel must generate to keep the system upright. Most systems like this use PID control, state-space control, or LQR (Linear Quadratic Regulator) methods to stabilize motion. The controller operates continuously, correcting errors hundreds of times per second. Reaction wheels are widely used in satellites because they allow attitu...