4C:http://www.google.co.in/search?hl=en&sugexp=les%3B&gs_rn=0&gs_ri=serp&pq=climbing+pine+tr
ees+in+jungle&cp=6&gs_id=fa&xhr=t&q=Chimp+climbing+pine+trees+in+jungle&bav=on.2,or.r_gc.r_pw
.r_qf.&bpcl=39468505&biw=1006&bih=605&um=1&ie=UTF8&tbm=isch&source=og&sa=N&tab=wi&ei=7
uu-UMqlI4KPmQW8q4DwCg ; Dec. 5, 2012
4D:http://www.google.co.in/search?hl=en&biw=1006&bih=605&q=ladder+to+climb+tree&bav=on.2,or.r_
gc.r_pw.r_qf.&bpcl=39468505&um=1&ie=UTF-8&tbm=isch&source=og&sa=N&tab=wi&ei=2-y-UP6-LsP
wmAXlm4HIDQ ; Dec.5, 2012)

Various reasons provoke design activity. Environment teaches or inspires man to create as designer, example- ladder. The desire to arm oneself with contraptions of technology to overcome the constraints imposed by nature is also a strong cause to indulge in design activity, example- bicycle, automobiles, bow & arrow, gun, etc. Human beings faces ecology or environment can also lead to design and creation, example- natural color scheme of butterflies, form of a tree or mountain, glide of a hawk, the movement of fish, structural element of beehive, etc. Whereas Porcupine or Chimp (plate 4A& 4B) do not have to face the same, since they are naturally equipped with the necessary devices to hold with claws or other things. Man as well created foot-rest for climbing the tree. Climbing with the help of foot-rest (plate 4C) is alternative to ladder. Observing the nature’s paradigm man could come up with solution In order to make up the said deficiency man has invented ladder (plate 4D).