Or
A node of the Style graph, in the Masks group.
A mask on where either mask is.
Takes: a (mask), b (mask) · Gives: mask
What it wires to
Its a input takes a mask, which these give: And, By facing, By material, By part, Edge pixels, Grow, Noise, Not, Pattern, Shrink, Solid pixels, Threshold.
What it gives, a mask, goes into: And, As a number, Choose by mask, Glint, Grow, Not, Shrink, Step where masked.
In the app, drag a wire from one of its dots: every dot the wire fits is ringed.
How it fits with the rest: the Style graph in the manual.
In the same group
Threshold · By part · By material · By facing · Noise · Pattern · Solid pixels · Not · And