This operator generates repeating filtered squares. The output is one if inside the box or zero if outside, and can be used to mix between colors or materials.
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.
The random seed output is only valid if using a single layer.