You can use the TORUS command to create a ring-shaped solid similar to the inner tube of a tire.
A torus is defined by two radius values, one for the tube and the other for the distance from the center of the torus to the center of the tube.
With the 3P (Three Points) option of the TORUS command, you can define the circumference of the torus by specifying three points anywhere in 3D space.
The torus is drawn parallel to and bisected by the XY plane of the current UCS (this may not be true if you use the 3P [Three Points] option of the TORUS command).
A torus may be self-intersecting. A self-intersecting torus has no center hole because the radius of the tube is greater than the radius of the torus.