A dry foam consists of thin liquid walls separating gas cells, such as in soap suds. A foam is called wet when the liquid pools at the intersections of cell walls. It is well understood how to “decorate” the intersection of a weightless dry foam to produce a weightless wet foam in its equilibrium state.
The art of crocheting can produce a stunning variety of aesthetically pleasing objects from the same skein of yarn. Some of them defy our intuition. Take, for example, the Klein bottle, a surface which like a sphere, has no edges or rims, but unlike a sphere does not have an inside and an outside—it has … [Read more…]