Some of the workshop pieces are one-off. I am experimenting with ideas, and come up with one or two things that are worthy of publishing. Some do not fit into a series. Sometimes the uniqueness is enough, the uniqueness makes them special. Other times I am just not in the mood to pursue the idea further. Sometimes when progress on one idea is slow and discouraging, I step away and create something totally unrelated before I can continue.
I think this one came about from a combination of the above reasons.