Kommentar zu Divrej Hajamim II 4:5

And its thickness was a handbreadth [i.e.] its bottom and its walls, but at its mouth it was thin, spread out and flattened.

like the work of the brim of a cup used for drinking, upon which is depicted a lily flower.

it contained three thousand It contained this amount, but in I Kings (7:26) it is written: “It contained two thousand baths.” The heaped measure was a third, for a bath is three seah, as is said: (Ezek. 45:11): “The ephah and the bath shall have one volume.” Thus you have six thousand seah. This equals a hundred and fifty purifying pools for four thousand seah equal a hundred mikvaoth. And we find also for the remaining two thousand seah fifty mikvaoth, and even if you divide the vessel according to the measure that the Rabbis computed, namely a cubit by a cubit by the height of three cubits for a mikvah, you will find the same: for the height of three cubits, which was square, and which was ten by ten from its brim to its brim, are a hundred mikvaoth, and for the height of two cubits, where it was round, ten by ten from its brim to its brim around equal fifty mikvaoth, because a square is a fourth more than a circle.