Plate 13A Coil Spring	13B Tendrils Holding	13C Door Closer Coil Spring

(Source : 13A : http://www.google.co.in/search?hl=en&q=Coil%20spring&bav=on.2,or.r_gc.r_pw.r_
qf.&biw=1328&bih=574&noj=1&um=1&ie=UTF-8&tbm=isch&source=og&sa=N&tab=wi&ei=T8IzUL
_hL9HOrQevrYDAAg
13B : http://www.google.co.in/search?hl=en&q=climber%27s+tendrils&bav=on.2,or.r_gc.r_pw.r_qf.&
biw=1328&bih=574&um=1&ie=UTF-8&tbm=isch&source=og&sa=N&tab=wi&ei=b8AzUO76Ls3RrQf
97YDYDA ; Aug. 21, 2012
13C : http://www.google.co.in/search?hl=en&q=Door+Coil+spring&bav=on.2,or.r_gc.r_pw.r_qf.&biw=
1328&bih=574&um=1&ie=UTF8&tbm=isch&source=og&sa=N&tab=wi&ei=f8UzUKXJK4HNrQe7k4Bw
#um=1&hl=en&tbm=isch&sa=1&q=Door+close+spring&oq=Door+close+spring&gs_l=img.12...60670
.61851.0.64094.5.5.0.0.0.0.0.0..0.0...0.0...1c.B_vvwiNFDU&pbx=1&bav=on.2,or.r_gc.r_pw.r_qf.&fp=
e2ad3fd6e808f277&biw=1328&bih=574 ; Aug. 21, 2012)

Coil form has some properties that make it well suited to springs. It is used as shock absorbing suspension device (plate 13A) for motor vehicle to various machines. Coil form can bear the weight of an object while in compressed position and returns to the original position once the object is lifted from the place. The elasticity of the material in coil allows spreading out the deformation. It provides a range within which the material is able to snap back to its original form. The coil in nature similarly holds the tendrils (plate 13B) as support to climbing. Door closer coil-spring (plate 13C) is used for automatic door closing.

Helicoids

Helicoids are an extension of the Coil Paradigm. Helicoids may be visualized as a helix, oriented vertically, and centred around the z-axis, with each point on the helix connected to the axis by a line parallel to the x-y plane (plate 12C).