I thought a diamond shape would be fun and bold, so I worked out a way to make it charm square friendly.
14" Diamond Lattice Block
For each block you will need:
(4) low volume 5" squares
(5) Diamond Blocks, which consist of (5) colorful 5" squares and (5) 3.75" squares
5" Diamond Block
1. To make one diamond blocks take one 5" square and cut it on the diagonal both ways to end up with 4 triangles.
2. I find it easiest to press creases into the 3.75" square by folding it in half and then in half again. Line up a triangle (right sides together) so that the point is on the center crease line and sew along the side (1/4" seam).
3. Press open, and repeat on the other side. It may be helpful to trim off the overhang before continuing to the final two sides.
4. For the last step, trim your block to 5" square, making sure to leave 1/4" seam allowance beyond each point.
You will need five of these diamond blocks to make one 14" lattice block. It's definitely faster if you chain piece.