At any rate, the earliest known structure actually discovered, a prehistoric tomb found in the sands at Hieraconpolis, is already right-angled. As Lethaby reminds us, modern people take squareness very much for granted as being a self-evident form, but the discovery of the square was a great step in geometry.[4] It opened a new era in the story of the builders. Early inventions must have seemed like revelations, as indeed they were; and it is not strange that skilled craftsmen were looked upon as magicians. If man knows as much as he does, the discovery of the Square was a great event to the primitive mystics of the Nile. Very early it became an emblem of truth, justice, and righteousness, and so it remains to this day though uncountable ages have passed. Simple, familiar, eloquent, it brings from afar a sense of the wonder of the dawn, and it still teaches a lesson which we find it hard to learn. So also the cube, the compasses, and the keystone, each a great advance for those to whom architecture was indeed "building touched with emotion," as showing that its laws are the laws of the Eternal. Maspero tells us that the temples of Egypt, even from earliest times, were built in the image of the earth as the builders had imagined it.[5] For them the earth was a sort of flat slab more long than wide, and the sky was a ceiling or vault supported by four great pillars. The pavement, represented the earth; the four angles stood for the pillars; the ceiling, more often flat, though sometimes curved, corresponded to the sky. From the pavement grew vegetation, and water plants emerged from the water; while the ceiling, painted dark blue, was strewn with stars of five points. Sometimes, the sun and moon were seen floating on the heavenly ocean escorted by the constellations, and the months and days. There was a far withdrawn holy place, small and obscure, approached through a succession of courts and columned halls, all so arranged on a central axis as to point to the sunrise. Before the outer gates were obelisks and avenues of statues. Such were the shrines of the old solar religion, so oriented that on one day in the year the beams of the rising sun, or of some bright star that hailed his coming, should stream down the nave and illumine the altar.[6]