Wumpus

Copperbox revision 829.

I've added a toy implementation of a new approach to vector drawing with a new the picture type. Currently it just has one geometric primitive (polygon) and one composition operator (<>) horizontal concatenation.

Its derived from Peter Henderson's original functional approach to pictures in that the primitives (polygons) are represented solely as vectors (no points not even an origin). Polygons are become pictures inside a binary tree which tracks the bounding rectangle (i.e. the coordinate free measures of width and height rather than alternate corners which would mean points and induce coordinates) of the child nodes and their displacement (again a vector). The only appearance of points so far is supplying the origin to the drawing / evaluation procedure. Adding other composition operators should be easy, but it remains to be seen whether this approach handles the affine transformations convincingly (scale, rotate, translate etc.).