If that is true "curly" grain, the dark lines will turn to light lines and vice versa when you move it back and forth in the light. That is known as "chatoyancy" or cat's eye effect.
From Wikipedia: "In woodworking[edit]Chatoyancy can also be used to refer to a similar effect in woodworking, where certain finishes will cause the wood grain to achieve a striking three-dimensional appearance; this can also be called pop-the-grain, wood iridescence, moire, vibrancy, shimmer or glow.[4] This effect is often highly sought after, and is sometimes referred to as "wet look", since wetting wood with water often displays the chatoyancy, albeit only until the wood dries. Oil finishes, epoxy, and shellac can strongly bring out the "wet look" effect."
What you got there, Clint, is probably an 11 on a scale of 10! I love it!