Got some really nice Moda Fabric cheap and decided to to do a Rail Fence using 4 fabrics. I sewed the all 4 together and cut two 8 inch blocks. When I turn them to make the Fence, they dont line up. One side measures 8 and one side 8 1/4, so you cant sew them together. What did I do wrong? Im not a math wiz so its a problem. Appreciate any input you can give me.