Modifed to output gcode that is compatible with K40 style laser cutter running Marlin (https://github.com/lansing-makers-network/buildlog-lasercutter-marlin).
I couldn't get the original version from LMN repo to work with LMN's Marlin as it never set the laser intensity on the M3 command.
This works form me, but YMMV. Very limited testing. Never leave your laser cutter unattended while it's powered/operating. Keep a fire extinguisher close by, wear saftey googles, and be afraid!