Just sharing this interesting idea! not mine btw.
What is the advantage in the moving head (though, I do like the “ooze guards”)? It doesn’t seem to save any space.
@Carlton_Dodd no space saving benefits, the idea is to stop leaky bowden from oozing when idle and immediate ready for print when switching between nozzles rather than prime the nozzle first and wipe before printing.
@Melvin_Chen AH! I have no experience with duals, or Bowden, so that was not obvious to me. Looks like it solves the problems pretty nicely!
Great design! I Like the speed of dual and the ooze guards too. Keep up the great ideas!
Interesting approach
Another benefit would be the heads having no chance of colliding with the parts while not in use.
Genial idea! An easy way to stop the leaking that can be applied also to a single extruder.
Is there the design and how to build it anywhere ?
Excellent! At last I see this working live 
You say it comes from elsewhere, can you post the source?