Some of products have also found very useful feature from the bellow principle of bending elasticity. The grip of tracking shoe-sole (plate 19A) have adopted similar design feature for better gripping and manoeuvring. Popularly traditional cycle-rickshaw rubber ‘bellow horn’ (plate 19C) is found in the Indian-subcontinent. The application of bellow in design has exhibited large numbers of innovative designs (plate 19B). Bellow mechanism, thus reflects the bending paradigm for multiple application and manoeuvring.

(Source:http://www.google.co.in/search?um=1&hl=en&tbm=isch&sa=1&q=Bellow+caterpillars&
oq=Bellow+caterpillars&gs_l=img.12...8535.12019.0.13902.12.10.0.0.0.0.0.0..0.0...0.0...1c._u7z
H3O7rWg&pbx=1&bav=on.2,or.r_gc.r_pw.r_qf.&biw=1328&bih=574&ech=1&psi=9bo5UJebBczq
rQf6kIHICg.1345960714226.4&emsg=NCSR&noj=1&ei=Frs5UMGJGMforQef6oD4DA ; Aug. 26, 2012)

Plate 20A ‘V’ Shaped Foldable Design		20B ‘V’ Shaped Garden Cover

Exercise: Design a construction of bridge (scaled) that would carry the weight and may be closed very easily. Specify the scale and the approximate weight to be carried.

Bellow design has helped designers to innovate temporary cover (plate 20B) for various purposes including for the garden (nursery). Because of its expandable quality the same is used for temporary covering.  Usually they are built for temporary purposes. The above diagram (plate 20A) explains the technique to construct the structure step by step.
Step 1: Place a flat sheet of corrugated cardboard between two points. For example- between the arms of a chair; now push down and see how easily it bends.
Step 2: Fold the sheet as shown and using tape or string fasten the open end of the V so it won't slip and go flat when you press on it. An easy way to do this is to make slits in the cardboard and with 2 knots in a piece of string, slit the string into the slit so the knots stop on the outside of the cardboard slit.
Step 3: Now push down and feel the strength a fold can make!