Physical commodities are known for an interesting phenomenon that I refer to as "bowl bottoms, spike tops". I believe I may have learned of this concept from Chick Goslin's book, "Trading Day By Day". This phenomenon occurs particularly with physical commodities because as prices rise in a parabolic way, eventually high prices destroy demand, following which prices tend to plunge rapidly downward. Thus, this is called a "spike top". On the other hand, when prices are in a downtrend, they tend to slowly lose momentum and gradually bottom out as demand begins to slowly and steadily build until prices begin to drive higher once again.
Wheat example #1
Wheat example #2
