The "trotting horse lamp" has been known in China since before 1000 CE. It is a lantern which on the inside has cut-out silhouettes attached to a shaft with a paper vane impeller on top, rotated by heated air rising from a lamp. The silhouettes are projected on the thin paper sides of the lantern and appear to chase each other. Some versions showed more motion with the heads, feet or hands of figures connected with fine iron wire to an extra inner layer and triggered by a transversely connected iron wire. The lamp would typically show images of horses and horse-riders.