a.�qAeroplane propeller, Bicycle wheel hub, Crab-like creature's claw, Fish with iridescent scales, Fungal growths on tree bark, Gear mechanism, Insect larvae, Leafy plant stem, Microscope slide, Muscle fibers, Nerve endings, Rocket thrusters, Screw threads, Seaweed strands, Spider silk threads, Tendrils of a vine, Watch gears, Wire filaments