'Wheel' in the Bible

Now while I was looking at the four living beings, I saw one wheel on the earth, by the side of the living beings, for the four of them.

The form of the wheels and their work was like a beryl; the four of them had the same form and design, and they were like a wheel inside a wheel.

And when he gave orders to the man clothed in linen, saying, Take fire from between the wheels, from between the winged ones, then he went in and took his place at the side of a wheel.

And looking, I saw four wheels by the side of the winged ones, one wheel by the side of a winged one and another wheel by the side of another: and the wheels were like the colour of a beryl stone to the eye.

In form the four of them were all the same, they seemed like a wheel inside a wheel.