As you can see, I'm no artist, but hopefully you get the idea. There are four pieces, a base on which the spores settle, and then three attached pieces which when added to the base create a shear flume. Water builds up in the gravity flume, creating pressure. The water then transfers through the holding box, whose purpose is to connect the vertical 2" pipe to a thin narrow shear channel. The cover fits over the base, creating a thin narrow opening through which water flows to create shear.
I've now ordered the raw materials to construct each of these components. Yay! Turns out custom-cut glass isn't so hard to find on the internets, even found a place in Washington to supply the glass pieces, so it shouldn't take them too long to ship to Friday Harbor.