An L-system, another way for recursion, a shape grammar is used to produce an order or a rule, a constructive rule to create a shape or geometry. the rule is used again to produce further development on the form, or so. the process keeps running and repeated again and again until it reaches a threshold or meets a goal.
In this experiment, the shape started with a simple pyramid, 3 sides pyramid. the algorithm takes each initial ( Pyramid) Geometry and alter between its sides and then find a normal and mirror the initial along the selected side. the generated geometry which is the result here is taken and used as input or as local initial to repeat the above process, and the image shown is the resulted shape.
Credit to Hoopsnake Discussion Group in Grasshopper3D website.