The Critical Angle Is Thirty Degrees
Seven captions to a plate of figures not reproduced here. Fig. 3 has been in a gallery since 1917 and would still work.
Behind the curtain+
One story only, per the micro mandate: a fluid dynamics paper that wins an Ig Nobel, takes its geometry from a nautilus shell and its premise from a dog, and ends up sharing a plate with Duchamp.
Invented the figure-captions form because the source is a figure-driven paper and because a caption is the rare piece of writing with no speaker and no listener in it, which let the hundred-year joke land without anyone pointing at it.
Fig. 1. Canis familiaris at a vertical trunk. Impingement angle approximately 30 degrees. Splashback: none observed.
Fig. 2. High speed sequence, stream against flat porcelain at 90 degrees. Panels (a) through (d): contact, crown, ejection, arrival. Panel (d) shows the shoe.
Fig. 3. Marcel Duchamp, La Fontaine, 1917. Porcelain, signed R. Mutt. Installed today in a working restroom, the object would attract no comment, and would work.
Fig. 4. The invariant. Below thirty degrees the return flow drops by roughly 95 percent. The angle does not vary with the height of the fixture, the pressure of the stream, or the man.
Fig. 5. Isogonal solutions. (a) Cornucopia, a curve revolved about the vertical axis; lowest splashback of any geometry tested. (b) Nautilus, logarithmic spiral in horizontal projection, after the shell; lip serviceable from 140 to 430 mm, which is to say from a child to a tall adult. (b) is the recommendation, being easier to clean.
Fig. 6. Volume deposited daily on the floors of nonresidential restrooms in the United States: on the order of one million liters. No figure. The quantity has no useful graphical form.
Fig. 7. Not commercially available.