A Shoo Fly calculator is available for different size and number of blocks for your own project.
Background: From 2½ inch strips, cut 4 squares and 4 half square triangles.
Medium Fabric: From 2½ inch strips, cut 1 square and 4 half square triangles.
Half Square Triangle Instructions
Cutting: Using a side right triangle ruler or template, cut half square triangles. Move ruler/template upside down for next cut when necessary.
Sewing: Sew ¼ inch seam on long side of triangle pair. Press seam to one side.
Layout Shoo Fly block as shown. Chain piece together using ¼ inch seam, sewing first rows, then columns. Press seams to one side.