The dimensions listed are confusing. One of the more important things to know with these shelves, is the depth of the smaller portion on either side.
This is a corner unit and you would likely have additional shelving units on either side continuing along the wall. It would look pretty silly if the depth of these additional shelves didn’t match up with the dimensions of this corner unit.
BTW, other sites seem to indicate this dimension I’m referring to above is actually 14 inches, so matching this with 18 inch deep shelves is going to make for unhappy customers.
The last three images are a different shelving unit than the first four images. The cut off corner is wider in the last 3 images. You can easily tell by counting the wavy lines. I like the last images, not the first ones and not knowing which one I’d get I’ll have to pass this one up.