Put two 7 1/2 inch blocks face to face

Sew a 1/4 inch seam on two opposite sides

Cut in three 2 1/2 inch strips in the direction of the seam

Join a centerpiece to the other colored strip

Press seams to the darker fabric

Lay the two units again face to face

Secure the opposite seams with pins and sew  a 1/4 inch seam on both sides

Cut again in three 2 1/2 inch strips

Join each of the center piece to the matching unit

Press seams away from center

Trim the blocks to 6 1/2 inch if necessary