Instant tree shaping[1][22] starts with mature trees,[23] :53 perhaps 6–12 ft. (2–3.6 m) long[4]:196 and 3-4in (7.6–10 cm) in trunk diameter,[13]:172 which are bent and woven into the desired design [23] :53 and held until cast.[24][25] Understanding a tree's fluid dynamics is important to achieving the desired result.[7][8]:69