A XML pointer-like scheme for addressing elements in a ZZ space.

Neighbours of a cell

	(cell).n(d.2,+).n(d.1,-)

Headcell of a cell

	(cell).negcell(d.2).poscell(d.1)

Searching for an intersection of two ranks (the cell itself won't count
so you can repeat it and get all crossings)

	(cell).intersect(d.2,+, (cell), d.1,-)

this is useful e.g. for searching clones:

	(cell).intersect(d.1,+, Color, d.clone, +).n(d.2,+)

to find the next cell giving the color through a clone.

XXX textual searching?

There should be a way to detect changes not only to cells but also 
expressions like this. Implementing settings would suddenly be a lot
easier.