  Inspired by the synchronized beating of cilia, we show that the collective
dynamics of hair-like fibers in a meniscus during fast drainage enables their
self-organization into multiple topologies including complex shape inversions.
By draining liquid from triangular-base hair bundles, we demonstrate their
transformations into concave hexagons, rounded triangles, circles and inverted
triangles. These topologically distinct shapes are quenched collective mode
shapes of the beating hair each corresponding to specific drainage rates of the
liquid, and cyclic shape re-transformations can be simply stimulated by
repeated immersion and drainage. The various topologies correspond to multiple
elastocapillary equilibria. Complex cellular materials with varying pore size
and density can be obtained by changing the drain rates from hair assemblies.
Due to its simple implementation and energy efficiency, these shape
transformations can have applications ranging from three-dimensional
lithography to smart multi-functional surfaces.
