It took me some research to understand what "twill" is when it comes to handweaving. Basically, you are creating staggered floats across the fabric, with the back being the reverse of the front. If using a rigid heddle loom, this is more easily accomplished using two (or more) heddles. Since I am swatching on a swatch maker, I did it by hand, which helped me understand just what twill is.
The warp is in light gray, the weft in dark gray, both are Cascade 220. If I understand the nomenclature correctly, this would be a 3/1 twill: over three threads, under one, repeat. On the front, the light gray barely shows.
The back is dramatically different. This is a good example of how swatching can help determine the results. If I had thought of it, I could have done a variety of twills in the swatch - 1/1, 2/1, 3/1, 4/1 - to see how the two colors work together.
When weaving in ends, I was careful enough that they don't show... much. The hemstitching really shows on the back, of course. That would be something to keep in mind when working something reversible.
Now that I have my four swatches completed, I'm eager to hear the guild presentation and see what other examples there are. Swatching has also taught me that I don't need to always be creating a finished object to enjoy weaving - or knitting, for that matter.