Assemble the Block
1. Sew together two red print triangles and two black print triangles in pairs (Diagram 1). Press the seam allowances toward the black triangles. Then join the pairs to make an Hourglass unit. Press the seam allowance open. Repeat to make a total of four Hourglass units.
2. Sew a black print 1-1⁄2×15" strip on each long edge of the red print 1-1⁄2×15" strip to make a strip set (Diagram 2). Press the seam allowances toward the black strips.
3. Cut the strip set into four 3-1⁄2"-wide segments.
4. Lay out the Hourglass units, Step 3 segments, and the black print 3-1⁄2" square in three horizontal rows (Diagram 3). Sew together the pieces in each row. Press the seam allowances toward the Hourglass units or center square. Then join the rows to make a block (Block Assembly Diagram). Press the seam allowances in one direction.