Ezekiel 1:16

These wheels appeared to have been skillfully made of some valuable material, the exact identity of which is unknown today. They all looked alike, and each wheel appeared to have another wheel, which seems to have been the same size, within it (attached to it). Another interpretation is that the wheels’ rims were concentric, a smaller one within a larger one. Evidently the axis of these wheels was the same and was vertical, forming a somewhat globe-like structure. [Note: Allen, pp. 33-34.] Chariot wheels seem to be what Ezekiel saw with other equally large chariot wheels intersecting the main wheels. These second wheels would have enabled the previously mentioned wheels to rotate left and right as well as forward and backward, as modern spherical casters do.