Mobile AR/VR headsets have a fraction of a desktop GPU's power but must still hit 90+ fps to avoid motion sickness. Eye-tracked foveated rendering is the trick that makes this possible: an inward-facing IR camera locates the wearer's gaze point tens of times a second, and the renderer shades a full-resolution "foveal" disc around it while quietly dropping resolution in the periphery, where human cone density — and therefore perceived detail — is already far lower. This simulator renders a live 3D tile grid whose per-tile resolution is resampled from the angular falloff function R(θ) around a moving gaze point, with real GPU pixel-cost and bandwidth-savings readouts, a saccade-driven auto mode, and a manual drag mode, plus a foveated/uniform toggle so the savings are visible directly.