RARiddel, here's a short article with illustrations of fiddleback, and several other types of figure in wood:
https://gobywalnut.com/blogs/articles/lets-talk-about-figureNo one knows what causes fiddleback. It may be more apparent with different cut orientations, but cut alone has nothing to do with the presence of fiddleback in a piece of wood. The effect comes from the way light reflects off of the undulating grain. It is thought to be genetic, but no specific gene has been found yet. It may be that it takes a combination of a tree having the correct gene, and some environmental factor to turn on that gene or genes. A tree that has fiddleback will have it from the trunk out to the smallest branches. In the 1920's and 1930's, attempts were made by the Northern Nut Growers Assn., and the USDA to propagate walnut trees with highly figured grain through grafting. These experiments were largely unsuccessful.
French, English, Turkish, Circassian, Persian, and Carpathian walnuts are all variations of the same species, Juglans Regia. There are a number of other Juglans Regia cultivars too. Black walnut is Juglans Nigra, Claro is Juglans Hindsii, and Bastogne is a hybrid cross between English and Claro.
