I have done a modified Rail fence up really quickly using the colors that erstan947 mentioned.
Three strips across (2 1/2" each)cut to 6 1/2" add one across the top of them (2 1/2" x 6 1/2") makes a 6 1/2" x 8 1/2" block. Alternate with a 6 1/2" by 8 1/2" square to make rows to the width you want.
Switch up the placement in each row, adding rows to reach the length you want.
Border with a 3 or 4" strip of a coordinate material and bind!