Originally Posted by dunster

A OBW generally uses only one fabric for most of the design. (There are sometimes other fabrics used for embedded hollow cubes, edges, borders, etc.) OBW blocks are also either octagons or hexagons. A S&W generally consists of blocks that combine a background fabric with the focus fabric and the blocks are usually square. But there are exceptions to any rule. Bethany Reynolds came out with the S&W books; Maxine Rosenthal came out with OBW much later.

Edited to add: Both methods involve layering fabric by lining up the same design element throughout the stack and then cutting through all layers, usually producing a kaleidoscopic effect.