Input a string to get a printable qrcode
cd qrcode2scad bundle install
cd qrcode2scad ruby qrcode2scad.rb "Hello World"
qrcode2.scad and qrcode.scad are created, they can be used in OpenSCAD and OpenJScad to create a STL file, then use your favorite STL to gcode tool, and print it.
Process in OpenSCAD can be long, it took 17 minute to compile qrcode.scad file on a laptop.