The white line outlining the diamonds establish the pattern for this design.
The way the center is filled in creates an impression of fused diamonds. There are any number of combinations and variations that can be stitched with this Bargello pattern (pp. 62-63 in Bargello: An Explosion In Color by Margaret Boyles) that will be very similar in their basic line; but the finished effect will be different. These treatments will change the look completely.
Three shades of gray and one white (Silk and Ivory) were used. To draw the eyes to the center of this 
Bargello needlepoint design, I used silver-black metallic braid to create a nice accent.
[...] Day 19 [...]