Prompt
Conceptual miniature diorama, 16:9 wide composition, on a fully transparent background with a real alpha channel — alpha = 0 at the edges, not white, not colored, no checkerboard pattern; a soft semi-transparent black shadow in the alpha channel grounds the model, darkest at contact beneath the base, fading outward.
A small figurine runner in a red singlet and grey shorts strides on a treadmill whose belt surface is painted as a road: matte grey asphalt with white dashed lane markings running along the belt. Seen in side view, the front half of the treadmill housing is cut away in a clean vertical cross-section, revealing the belt's closed loop — the road surface runs forward over a front roller and a rear roller, and the same belt returns flat and taut underneath the running deck, joined to both rollers so the circuit is one continuous connected loop. At the far end of the platform a small doorway structure stands fixed at the platform's edge; the road exists only on the belt and ends there. Matte painted-metal figurine surfaces, smooth matte asphalt, soft even studio light, one compact oval contact shadow beneath the treadmill base. The whole treadmill, runner and doorway sit fully inside the frame with clear margin on every side; nothing touches or crosses any edge.