The four creatures are now high in the air above Ezekiel, a dreadful and awe-inspiring sight for a man of Ezekiel's time. Their "rings" obviously are the flames from their tip-jets, seen from below--the only part of the wheel now visible from far below. And the rings _would_ be full of eyes. When a jet or rocket motor is operating there is a shock wave generated in the tailpipe which tends to cut the exhaust gas into segments. Time exposures of jet aircraft at night often show this. When a tip-jet is operating, these bright, evenly spaced spots give it the appearance of a string of pearls, "... full of eyes round about them...." _19. And when the living creatures went, the wheels went up by them: and when the living creatures were lifted up from the earth, the wheels were lifted up._ Ezekiel makes it clear that he does not know whether the men are lifting the wheels or the wheels lifting the men, but both went up together. _20. Withersoever the spirit was to go, they went, thither was their spirit to go; and the wheels were lifted over against them: for the spirit of the living creatures was in the wheels._ This is a most sophisticated opinion. Although Ezekiel was describing only what he saw, he could not help but have some opinions about the creatures. In verse nineteen he makes it clear that he does not know whether man is lifting the machine, or the other way around, but here he makes it clear that whichever, there is no doubt that the creatures are _controlling_. They are not being carried off by the will of the wheel. _21. When those went, these went; and when those stood, these stood; and when those were lifted up from the earth, the wheels were lifted up over against them: for the spirit of the living creatures was in the wheels._ This carries the idea of control one step farther. Not only are the men controlling the wheels, but they are self-controlled: They are flying in formation. _22. And the likeness of the firmament upon the heads of the living creatures was as the colour of terrible crystal, stretched forth over their heads above._ Perhaps this verse was moved out of it's original position, for it returns to the description of the creatures. You may have noticed that many of the verses are written so that it is in part, an enlargement of the thought put forward in the preceding verse, and part new thought, to be enlarged upon in the following verse. Verses twenty-two and twenty-three _seem_ to go together. Both would fit the rest of the chapter better if they were between verses twelve and thirteen. What is meant by "firmament"? These people had no term for a hollow-sphere. Most spherical objects were not hollow. They had no soap, so they had no soap bubbles. The most common thing to compare a hollow sphere to was the sky, the bowl of the heavens--the firmament. This crystal-clear bubble was over the heads of the creatures, one on each creature.