This article is from the Skydiving FAQ, by Barry Brumitt with numerous contributions by others.
The canopies used today bear little resemblance to the classic round
canopies of years gone by. Today, nearly all jumpers and jump schools
use "square" canopies for parachuting. These canopies are actually
rectangular in shape, and when open, act like an airplane wing (or an
airfoil). They are more like gliders than umbrellas.
The aerodynamics of the square canopy provide it with exceptional
maneuverability, allowing the jumpers to land almost anywhere they
wish. This wing shape also provides tippy-toe soft landings for even
the novice jumper. The days of landing like a sack of flour are
history. Most students land standing up on their first jump.
 
Continue to: