So named because of the diamond shapes that showed up between the woven diamonds.
You could leave out the optional stitches and still have a nice design. I kind of like it this way—half and half.
I apologize for the dimly lit photo. The orange yarn tended to overpower the pattern if light shone on this square. The sample shows the four outer diamonds with the optional center U3s. This isn’t my favorite variation; it’s more here as an example to illustrate how a design can look good on paper, but may not look so good when woven—the proof is in the weaving.