When it comes to optical illusions in quilting, Karen Combs wrote the book (literally). Her most recent book, Celtic Pieced Illusions, includes her stunning Celtic Rings quilt.
To make it easier for quilters to create 'quilts of illusion', Karen also designed the Shade Cascade fabric line. The collection includes 21 bright colors, such as teal (as seen below), shamrock, iris, paprika, and others. The fabric line solves the problem of "finding" a light, medium and dark fabric within a color family. Each fabric has four gradations, from light to dark, across a bolt.
In order to see how Shade Cascade can be used to create optical illusions, we created tumbling blocks in six different colors, using the first three shades from each bolt to create the three sides of each block. The illusion of three-dimensional blocks was convincing, as shown here.
Another Karen Combs fabric line is Crystal Fusion, which comes in 26 colors. We love the bold Crystal Fusion quilt pattern, below.
Images, courtesy of Karen Combs at Karen Combs Studio. Shade cascade fabrics, see Karen's Online Store, local quilting stores, and Blank Quilting. Crystal Fusion fabric line and quilt pattern, and other Karen Combs fabrics, see Avlyn, Inc.