Not

A node of the Style graph, in the Masks group.

A mask turned inside out.

Takes: mask (mask) · Gives: mask

What it wires to

Its mask input takes a mask, which these give: And, By facing, By material, By part, Edge pixels, Grow, Noise, Or, Pattern, Shrink, Solid pixels, Threshold.

What it gives, a mask, goes into: And, As a number, Choose by mask, Glint, Grow, Or, 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 · And · Or