The apocrypha has it that K’NEX were invented by two engineering students who had nothing better to do while smoking pot and scarfing pizza than to play with the pizza box lid lifters and their plastic drink straws.
K’NEX consist of rods and circular connectors. There are eight connection points on a full circle connector. Connectors are available in 2, 3, 4, 5, and 8 connection pieces. Rods vary in length. An isosceles right triangle built from connectors and rods will have a hypotenuse equal to the size of the next larger rod. Other parts include wheels and pulleys. At first, connectors and rods were color-coded by length. This practice is slowly ending as the designers color the pieces in order to color the model.
What we have here is a building toy that models support structures. While LEGOs model walls and floors, K’NEX models the skeleton of a building, something that even LEGO technics never quite does well. If some third party were to make a cross-connector for these two systems, they would rule the world.
However, most of the sets that the K’NEX people are designing are dinosaur-like monsters, that have small motors the make them walk. Other, smaller sets, have rubber bands that, when wound up, drive wheels or flap.
For the fall toy season of 2001, K’NEX, under license from FASA, will release sets of the 'mechs Mad Cat, Shadow Cat, and Cauldron Born.