Not long after the previous image was made, I heard the sounds of sheep and goats and shepherds close at hand. The tools of a shepherd's trade are rocks and shouts, and he can often fling both for considerable distances. Quite naturally I shifted my attention to matters closer at hand. Life in the desert or the steppes is simple, and the simple life can produce strong people. Over the centuries wave upon wave of warriors from the desert and the steppes have rolled over the cities of Central Asia, China, India, Mesopotamia and the Levant. Each new wave of conquerors slowly adopts the practices of the conquered civilizations and in turn becomes subject to decline. Then a new wave of hungry tribes sweeps in from the wilderness, and the process begins again. Religious laws attempt to arrest or slow these changes and preserve the (often mythical) purity of the pastoral past amid life in urban civilization