Corn mazes are deceptively difficult. With the corn growing far above the head of an adult, it is easy to get totally lost. The labyrinth turns out to be more complex than it first appeared.

The mazes make good metaphors for investors’ journey into the world of commodities. Over time, commodities boost returns and aid diversification. In the last few years the big commodities indices have far out-performed stocks. But they do not all move together.