shequilts

Beth:
This is tricky but do-able.
From the white:
Cut a block 4.5" square. Using an accurate measurement, cut a 2.25" square from one corner.

From the black:
Cut a 2.5" square. Using an accurate 1/4" ruler, mark a 1/4" "seam" line around all four sides.

With right sides together, place the black square in any corner of the white square. Follow accurately, the drawn seam line. Stitch from outer edge to center. ending at the junction of two marked lines. Back stitch one stitch to secure. Remove from the machine.

Open the new block with the black now in the upper left corner and finger press the seam you just made. Fold the top half of the block toward the bottom. You will have a "pucker" at what will be the junction of the two new seams. Carefully clip the pucker to within 2 threads of the drawn seam line.
The block should then lie flat and should be stitched from center to edge. (Use the "needle down" to make sure you start on the exact stitch of the previously sewn seam. You've completed a "Y" seam. open the block and press flat. Make certain the back seams are lying flat.