I made a quilt with all edges of blocks on the bias. The corner seams needed to be exactly in the corner, so I took my 12 1/2 in. ruler to the ironing board and drew the outline of the ruler onto the ironing board with PEN. (It's still on there.) When the block was completed, I laid the block onto the drawing and found out that I couldn't see the drawing anymore! So I drew lines on the bias extending beyond each corner so that I could see where the corner was. Then I pinned each corner so that the seam was on that line, starched it heavily, ironed it dry, and then then proceeded to sew the blocks together. It turned out perfectly.