Remember the first time you noticed how your hands got wrinkly when you stayed in the bathtub or keep it in water for too long?
Math. Math is under our skin, doing its mathy work, keeping our skin intact and unmelted.
Take a look:
That’s a model of a gyroid, which is a geometrical shape found all over the natural world. Mathematicians think that fibers of keratin in our skin are actually woven into this shape as well, which is important, because it means the skin can expand but keep its structure because the fibers have so many connections to one another. With this pattern, the fibers can “swell to fill a volume seven times greater than its original shape.”
That’s what’s happening when your skin wrinkles. It’s absorbing water, which makes it grow in volume. Since the rest of your hand is still the same size, your skin begins to wrinkle the same way a glove would if it was too big for your hand.