Dean said it twisted 1/4 turn about every 2 feet of length. Curly maple, or compression wood is a lot tighter, about 1/4" to 3/8" curls.
Curly Maple: Fiddleback Maple is also known as 'Flame Maple', 'Tiger Maple', 'Curly Maple', or 'Tigerstripe Maple'. Fiddleback Maple exhibits a dramatic change in the individual stripes or lines. As the incident angle of the light is slightly altered, the dark stripe becomes a light stripe, and the light stripe becomes dark. This visual phenomenon is known as 'chatoyancy' in the gemstone world, and its most dramatic form is seen in catseye chrysoberyl.
True Fiddleback figuring is not to be confused with "compression grain" or "stress grain" found where roots merge into the bole and also on the underside of large limbs. Some differentiate between Curly and Fiddleback figuring. For instance, curly cherry and curly birch can exhibit much swirls, waves and curls, though they are far more irregular and large, often appearing as flattened arches stacked one on top of another over the length of the board. Fiddleback Maple (Flame Maple, Tiger Maple) grain is generally considered to be more pronounced with tighter striping, sometimes measured as tight as several stripes per inch. Unlike many forms of curly grain, Fiddleback describes a series of tight, parallel (or nearly parallel) stripes running perpendicular to the length of the board.
In the United States, most use the terms Fiddleback Maple and Curly Maple synonymously. Fiddleback Maple boasts a three-dimensional series of alternately bright and dark stripes that shade into one another as the wood is slightly moved, thus producing an illusion of actual waves. Changes in brightness result from differential light reflection. Relatively high absorption by exposed fiber ends produces dark bands; reflection and diffraction from fiber walls cause bright bands. Because the fiber walls are curved sharply and act as concave or convex reflecting surfaces, any change in angle of view or incident light makes the apparent waves seem to shift. Again, the same light stripe becomes a dark stripe and vice-versa.
The illusion of undulations results from regular and repeated, parallel, wavy lines that produce an interference pattern on the exposed plane. Modern botany and science still cannot adequately account for what exactly causes the visually-stunning figuring in Fiddleback Maple (also known as Flame Maple, Curly Maple, Tiger Maple, Tigerstripe Maple). In conclusion, then, the cause(s) of the rare figuring seen in Fiddleback Maple is yet unknown. The mystery of Fiddleback Maple, in spite of electron microscopes and huge advances in the fields of wood technology, plant genetics, etc., for now remains unrevealed.
See a sample at:
http://www.rayjoneswoodboxes.com/curly_maple.htm
