Grammars

Before moving into grammatical generation of elements, there are important questions to answer   Should the grammar generate floors or columns?  Should it be context sensitive?  SHould pattern conflicts between adjacent floor or columns be resolved in the simulated annealing step (by the way, I'll be using simulated annealing)?
For now the start symbol with generate a ground floor and either a set of rows or columns.  By supporting both randomly there should be different emergent patterns to widen the variety of buildings generated.  The basics of the grammatical approach should not be too complicated.  Each symbol with evolve randomly into one of its descendants and then branching string will be terminated then the row or column has run out of the respective dimension on the building.  Here setting width and height as floats rather than a fixed number of floors will work better.

As part of the simulated annealing step I am considering a unordered "element soup" approach incase the user specifies elements that span multiple floors wants an element of out of normal alignment.  Pending better understanding of how the annealing step works this idea will be reviewed.