Assemble Hidden Square Blocks
1. Sew together a cream tone-on-tone 3-3/4x21" strip and a red print 3x21" strip to make a strip set (Diagram 9). Press seam toward red print strip. Repeat to make 14 strip sets total.
2. Place one strip set right side up on your work surface with the cream tone-on-tone strip at the top. Top with a second strip set right side down and red print strip at the top (Diagram 10). Cut layered strip sets into six 3"-wide layered segments. Do not separate layers.
3. Repeat Step 2 with remaining strip sets to cut 42—3"-wide layered segments total.
4. Sew a layered segment along one pair of long edges to make a block unit (Diagram 11; note that red print in upper layer is still at top). Press seam in one direction. The block unit should be 5-1/2x6-1/4" including seam allowances. Repeat to make 42 block units total.
5. Lay a block unit on work surface with wrong side up and red print squares in the upper right-hand and lower left-hand corners. Align the 45° angle of the acrylic ruler with left edge of block unit. Referring to Diagram 12, slide ruler up or down until its right-hand diagonal edge is 1/4" from seam intersection; use a pencil to draw a diagonal line on block unit. Repeat with remaining block units.
6. Layer a marked block unit atop a green tone-on-tone or green floral 5-1/2x6-1/4" rectangle; pin. Sew together with two seams, stitching 1/4" on each side of drawn line (Diagram 13). Cut apart on drawn line to make two triangle units. Press each triangle unit open, pressing seam toward green tone-on-tone or floral, to make two hidden square blocks. Each block should be 5-1/2" square including seam allowances.
7. Repeat Step 6 to make 84 Hidden Square blocks total.