|טז רָבוּעַ יִהְיֶה, כָּפוּל; זֶרֶת אָרְכּוֹ, וְזֶרֶת רָחְבּוֹ.||16 Four-square it shall be and double: a span shall be the length thereof, and a span the breadth thereof.|
And this has a particular meaning. The basis of this is a statement from Rav Shamshon Rephael Hirsch:
But then, what about the Giant's Causeway, pictured above? I suppose they are not exactly square -- most are hexagonal, though there are some with four sides, and they do have angles. And they look hewn, though the result of natural processes. I suppose there is always the exception that makes the rule. And this is why the Giant's Causeway seems so out of the ordinary.