The Commissioners' Plan did not in any way specify what the size of individual lots within the blocks should be, although the size and rectangular nature of the blocks lent itself to rectangular lots of equal size to fit into the block. A standard lot was deep, which was half the depth of the block, and wide, depending on the location. By removing most of the topographical features which had once defined lot boundaries, the grid turned land into a commodity, which could be easily bought and sold in roughly equal-sized units, thus rationalizing the real estate market. Zoning requirements also contributed to the order brought by the grid: the city required buildings on avenues to be no more than three stories, and those on the streets no more than two. This, of course, changed over time.