Right hand download: frogpad.com/Frogpad-Right.exe
Left hand download: frogpad.com/Frogpad-Left.exe
AutoHotKey .ahk source code: https://github.com/clarkm/dupepad/tree/master/autohotkey
MacOS 10.12 (Sierra) - MacOS 11 (Big Sur) and above:
Install Karabiner-Elements first
right hand download: click here to install, then click enable
left hand download: click here to install, then click enable
OS X 10.11 (El Capitan) and below:
Install Karabiner 10.22 first
right hand download: frogpad.com/private.xml
left hand download: frogpad.com/left/private.xml
Dupepad project for Windows & Mac by Clark: https://github.com/clarkm/dupepad