My colemak layout (without teensy button) http://configure.ergodox-ez.com/keyboard_layouts/qajjmk/edit

I aim for symmetry of modifier keys, primarily: I get Emacs Pinky quite quickly when using a standard (1 ctrl button) laptop keyboard.

Use ErgoDox EZ configurator (with my layout as the basis): http://configure.ergodox-ez.com/keyboard_layouts/qajjmk/edit

This great configurator has loads of extra keys that I had to add manually, and painfully, to a C file.

• Run teensy.app from teensy.dmg
• Press +L1 then teensy button (on the old layout, EZ layout configurator doesn't have this teensy button)
• Open newest .hex file
• Program
• Reboot