This operator generates staggered rectangular tiles. The output
coordinates have their fractional components set to map each tile
appropriately. As well, a random ID is generated per tile.
t inputs are not specified, global variables appropriate to
the current context will be used instead, as follows: (s,t) in the
shading contexts; (P.x,P.y) in the geometry and particle contexts; and
(X,Y) in the compositing context.