Dutch sculptor Theo Jansen works in an ususual medium: PVC pipe. But when you're creating giant kinetic creatures that appear to be alive, you use what works. Jansen explains his work on his "Strandbeest" website:
Since 1990 I have been occupied creating new forms of life. Not pollen or seeds but plastic yellow tubes are used as the basic material of this new nature. I make skeletons that are able to walk on the wind, so that they don't have to eat. Over time, these skeletons have become increasingly better as surviving the elements such as storm and water and eventually I want to put these animals out in herds on the beaches, so they will live their own lives.Engineers may enjoy Jansen's detailed explanation for how he gets the animals to walk.