I believe that what Ezekiel saw and describes as "a wheel in the middle of a wheel" is an orbital description of the Holy Spirit.
Excerpt from "Ezekiel's Vision of God":
Ezekiel 1:15-21 Now as I look at the living creatures, behold, a wheel was on the earth beside each living creature with it's four faces. The appearance of the wheels and their workings was like the color of beryl, and all four had the same likeness. The appearance of their working was, as it were, a wheel in the middle of a wheel. When they moved, they went toward any one of four directions; they did not turn aside when they went. As for the rims, they were so high they were awesome; and their rims were full of eyes, all around the four of them. When the living creatures went, the wheels went beside them; and when the living creatures were lifted from the earth, the wheels were lifted up. Wherever the spirit wanted go, they went, because there the spirit went, and the wheels were lifted together with them, for the spirit of the living creatures was in the wheels. When those went, these went; when those stood, these stood; and when those were lifted up from the earth, the wheels were lifted up together with them, for the spirit of the living creature was in the wheels.
If you look at an artist's rendition of "Ezekiel's Vision of God", you will see Father God on his throne, an angel and the "wheels". We know that the wheels are not Father God, nor Jesus, nor an angel. That only leaves the Holy Spirit in orbital form:
Today, we are capturing the reality of the Holy Spirit with photographs and videos. This orbital form of the Holy Spirit is also known as the "supernatural orb". And, I believe that it is time that some of us Christians put this highly misunderstood supernatural orb in its rightful place as the Holy Spirit.
The orb pictures are usually one-dimensional. Orbs are actually three-dimensional or round (orbital). To make it three-dimensional or round, take the two orbs in the picture below and put one inside another, and given they were the same size, you can see that they would appear as "a wheel in the middle of a wheel":
And, "their rims were full of eyes":
The orb can also be seen as colorless or the multiple colors of beryl, "The appearance of the wheels and their workings was like the color of beryl".
Shown are orbs that are the beautiful multiple colors of beryl:
And spirits are sometimes seen in orbs, "for the spirit of the living creature was in the wheels".
Here is a link to a picture with the face of a spirit in the orb:
Spirits are also known for traveling through orbs, "Wherever the spirit wanted to go, they went".
Here is a picture of orbs in flight:
With love to my brothers and sisters. Peace be with you and God bless.