We two-leggers (humans) invent all kinds of explanations for natural phenomena. But some of our eight-legger buddies skip the math and just do their thing. A good example is this cobweb that I felt I should photograph before annihilating it in order to maintain a nice clean house (the web had been abandoned, so no spider was made homeless by my crass act). Its shape is intriguing; it resembles an inverted elliptic paraboloid, also known as a paraboloid of revolution.
The spider probably just calls it a dining room. Either way, it’s a fascinating shape. If it were two-dimensional, it resembles an inverted catenary arch, the shape a chain makes when suspended from its two ends and allowed to hang free. It turns out that a catenary is only superficially similar to a paraboloid, but you sure could have fooled me.
I wish the spider web were saddle-shaped, because that’s called a hyperbolic paraboloid. I love that term. Think the shape of a Pringles™ potato chip. Just eating them boosts your mathematical abilities I’m sure, and for sure your daily intake of sodium.
Picture credits: The cobweb is mine, the other two are from Wikimedia Commons