Paste a PNM image into another PNM image. More information: https://netpbm.sourceforge.net/doc/pnmpaste.html.
pnmpaste x y path/to/image1.pnm path/to/image2.pnm > path/to/output.pnm
stdin into the specified image:command | pnmpaste x y path/to/image.pnm > path/to/output.pnm
true while black pixels represent false:pnmpaste -and|nand|or|nor|xor|xnor x y path/to/image1.pnm path/to/image2.pnm > path/to/output.pnm