This video showcases how the RHS of a shape rule can be edited in the Shape Machine. The rules are represented in the classical shape grammar format with the two sides of the production system, LHS and RHS, the arrow (>) inbetween and the two registration marks on either side of the middle arrow (>) to fix the spatial relation between them. The first vignette demonstrates the design of a RHS in the form of a schema t > t(x), for x a Root2 isosceles triangle and t(x) a translated copy of the Root2 isosceles triangle. The second vignette shows the design of a more complex RHS in the form of a schema x > x  prt(x) + y, for x a Root2 isosceles triangle, prt(x) a part of the Root2 isosceles triangle that is erased, and y a new set of lines in some spatial arrangement with the left over part of the Root2 isosceles triangle. Clearly this last action can be described in a number of alternative ways (Economou and Kotsopoulos, 2014).
