Proper Size for a Tomb

If a man sold to his fellow a place in which to make a tomb, and likewise, if a man was commissioned by his fellow to make a tomb, he must make the inside of the vault four cubits by six and open within it eight niches: three on this side, three on that side, and two opposite [the doorway]. The niches must be four cubits long, seven handbreadths high, and six handbreadths wide. R. Simeon says: He must make the inside of the vault four cubits by eight and open within it thirteen niches: four on this side, four on that side, three opposite [the doorway], one to the right of the doorway, and one to the left. He must make a courtyard at the opening of the vault, six cubits by six, space enough for the bier and its bearers. And he may open within it two vaults, one on either side. R. Simeon says: Four, one on each of its sides. R. Simeon ben Gamaliel says: All depends on the nature of the rock.