1. Sew together one red print 2x5" rectangle and two blue print 2x5" rectangles to make a Rail Fence unit (Diagram 1). Press seams toward blue print rectangles. Repeat to make 12 Rail Fence units total.
2. Join two Rail Fence units to opposite edges of blue print 5" square to make block center (Diagram 2; note direction of seams in units). Press seams toward square.
3. Join assorted white stripe or print large triangles to opposite edges of a remaining Rail Fence unit to make a block side (Diagram 3; note direction of seams in unit). Press seams toward triangles. Repeat to make a second block side.
4. Lay out block sides and block center in three diagonal rows (Diagram 4). Join rows; press seams toward block center. Add assorted red print small triangles to corners to complete a block. Press seams toward small triangles. The block should be 12-1/2" square including seam allowances.
5. Repeat steps 2–4 to make a second blue block.
6. Using the red print 5" square and remaining white large triangles and Rail Fence units, repeat steps 2–4 to make a red block (Diagram 5).