Finished block should measure 12.5 x 12.5 in.
Use 1/4" seam allowance
From background fabric cut four 3 1/2" squares and one 3 1/2" x 15" strip
From color 1 cut one 3 1/2" x 15" strip
From color 2 cut four 3 1/2" x 6 1/2" rectangles
Sew color 1 and background strip together
Cut into four 3 1/2" sets
Place square of background on the end of the color 2 rectangle, stitch diagonally from corner to corner, then trim 1/4" from the sewing line. Press seam allowance toward color 2 and away from background.
Sew together four sets like the mini block above
Then sew the four mini blocks together to create a finished Oh Susannah! square. Try to match your seams a little better than I did in the center :P oops!
For those asking, the fabrics I've been using with the tickets in them are from the Punctation line by Moda.