Quilt Notes: GRANDMA'S SURPRISE (see also GRANDMOTHER'S OWN below) is illustrated in Maggie Malone's 5,500 QUILT BLOCK DESIGNS. The "surprise" probably refers to a surprise birthday party, but there is a geometric delight to be had also when the design is tiled (see below), and the octagon unexpectedly and beautifully recreates itself into a matrix of circles and diamonds with a perfect Maltese Cross at the center. In fact the category on Maltese Cross designs in Barbara Brackman's ENCYCLOPEDIA OF PIECED QUILT PATTERNS reproduces three examples with this same arrangement of triangles (dated to 1930-31, see KALEIDOSCOPE QUILT, etc.), but with very different distributions of dark and light. This variation is by far the most elegant.
For another "granny" design, see illustrated left GRANDMOTHER'S OWN (animation repeats 6x), an 1890s, 4-patch block, listed in the Ladies Art Company Catalogue #166.
More examples like GRANDMAS' SURPRISE at this site, with illusionary circular designs created by straight-edge polygons in the tiling pattern, include:
BLOCK STAR (irregular dodecagon)
BEAUTIFUL STAR (dodecagon)
JAPANESE FLOWER (irregular dodecagon)
MORNING PATCH (octagon)
PIGEON TOES (octagon)
TWIST PATCHWORK (octagon)
To learn more about optical quilt motifs, see OPTICAL ILLUSIONS FOR QUILTERS, by Karen Combs (1997).