The two of the great feats of civil engineering accomplished by the engineers of Ancient China are as follows:
1. The great wall
2. The grand canal.
The formulation of the great canal enables to ship of grain from southern China to Beijing to feed the standing soldiers around northern borders. The great wall was built during the period 1368-1644 (Ming Dynasty)
Generally it is true that loess deposits usually blanket an area in an even layer, although it should be noted that things like wind and rain patters can affect this distribution.