The Snowball pattern looks like an octagon with four triangles sewn on the corners to make a square:
A few years ago, an idea surfaced to replace the octagon pattern with a square and replace the triangles with four squares. The small squares are sewn to the corners of the large square; sewing lines are drawn or eyeballed.
With Perfect Patchwork Templates, there is no more guessing where the sewing line should be. The corners of the right-triangle templates allow for perfect alignment on a square. Contact points and perfect 1/4" (6 mm) seams are the keys to accuracy.
Trim away the portion of the square that is just below the triangle, if you wish. In this book, this optional piecing technique is called "trick piecing."
Expanding on a Good Idea. There are many other shapes where the Snowball Trick can be used. Traditionally, they would require these odd-shaped templates.
Instead, use the "Snowball Trick" to trick-piece the appropriate triangle(s) to a square.
Excerpted from the Encyclopedia of Patchwork Blocks, Volume 2 published by Michell Marketing, Inc. ©1995 Martha G. Michell