The posts of the temple were square, and also the face of the sanctuary; the appearance of the one like the appearance of the other.
All Commentaries on Ezekiel 41:21 Go To Ezekiel 41
George Leo Haydock
The threshold was four-square. That is, the gate of the temple was four-square, and so placed as to answer the gate of the sanctuary within. (Challoner)
It was not an arch, though not a perfect square, 3 Kings vi. 34.