Charles Ellicott Commentary 1 Kings 7:31

"And the mouth of it within the capital and above was a cubit: and the mouth thereof was round after the work of a pedestal, a cubit and a half; and also upon the mouth of it were gravings, and their panels were foursquare, not round." — 1 Kings 7:31 (ASV)

And the mouth. —This is very obscure, and in our version unintelligible. Keil renders it: "And its mouth (the laver) was within the capital, and a cubit above it; and its mouth (the capital) was round, like a pedestal, a cubit and a half; and on the mouth was carved work, and its panels (the mouth) were square, not round." But the rendering of the word “mouth,” sometimes for the laver, sometimes for the capital, is arbitrary, and the whole is still obscure.

As the circular stand (or capital) was half a cubit deep, it seems that the lower surface of the laver was a cubit above the “mouth.” If the laver were emptied by a tap near the bottom, this circular stand may have received the drippings. And as the top of this base would be square in plan, and the stand circular, there would, of course, be spaces left at each corner, which might be the engraved “panels” referred to.