The camber-stages generator

Cambered against the wet load. A 12 m composite beam whose flexural rigidity rises from 94 to 260 kN·m² when the slab sets, so the first two loads are carried by the bare steel and the rest by the composite section. Fabricated with 25.3 mm of camber, it moves through -20.7, 0.0, 7.5, 12.7 mm as the four stages arrive — 0.0 mm on the day the slab is poured, and 12.7 mm at the end, which is one part in 947 of the span. The largest curvature it ever has is 25.3 mm of hog, and it has that with nothing on it. Every shape is drawn at the same exaggeration and the drawing is a diagram of a proportion: the vertical scale is 119484 times the horizontal.

1 essay calls camber-stages. The drawing above is what it returns with no arguments at all; every call below passes it something, because a placement that passes nothing draws whichever member of the family the generator happens to default to rather than the one its essay argues about.