1. Gather two 3-7⁄8" squares from one print; four 1-1⁄2" squares, two 3-7⁄8" squares, and four 3-1⁄2" squares from a second print; and a 3-1⁄2" square from a third print.
2. Use a pencil to draw a diagonal line on wrong side of the print No. 1—3-7⁄8" squares and the print No. 2—1-1⁄2" squares.
3. Referring to Diagram 1, layer a marked print No. 1—3-7⁄8" square atop a print No. 2—3-7⁄8" square. Sew together with two seams, stitching 1⁄4" on each side of drawn line. Cut pair apart on drawn line to make two triangle units. Press open each triangle unit, pressing seam toward darkest print, to make two triangle-squares. Each triangle-square should be 31⁄2" square including seam allowances. Repeat to make four triangle-squares total.
4. Align a marked print No. 2—11⁄2" square with one corner of print No. 3—31⁄2" square (Diagram 2; note direction of marked line). Sew on drawn line. Trim excess, leaving 1⁄4" seam allowance. Press open attached triangle. In same manner, add marked print No. 2—1-1⁄2" squares to remaining corners of 3-1⁄2" square to make a Snowball unit (Diagram 3). The unit should be 3-1⁄2" square including seam allowances.
5. Referring to Diagram 4, sew together triangle-squares, print No. 2—3-1⁄2" squares, and Snowball unit in three horizontal rows. Press seams toward 3-1⁄2" squares. Join rows to make a block. Press seams away from Snowball unit. The block should be 9-1⁄2" square including seam allowances.
6. Repeat steps 1–5 to make 21 blocks total.