This is the same quantum Otto-cycle heat engine — a discrete-level working substance stepping through unitary compression, hot-bath thermalization, unitary expansion and cold-bath thermalization — rendered as an orbitable 3D energy tower instead of a flat chart. Ring spacing along the rod visualizes the level spacing ω tightening and loosening during the two unitary strokes, while bursts of glowing quanta fired in from the cold plate or the hot plate visualize heat crossing the boundary during the two thermalizing strokes. Tune the hot and cold level spacings and bath temperatures to watch the burst direction, ring population and live efficiency readout respond exactly as the formula η = 1 − ω_cold/ω_hot predicts, bounded by the Carnot limit set by the temperatures.