I have used several different all-in-one printers over the years (mostly
Canon). They all did two-sided printing the same way: print the odd page
numbers first, then ask the user to take those printed pages and turn them
around and put them back in the input paper tray to have the even numbered
pages printed on the back of the odd numbered pages.

My latest, cheap Canon all-in-one printer, MG3600, does it differently in a
way I can't figure out how it does it!

This new printer when printing double-sided will print page one, then pull
the page back into the printer and print page 2 on the back of page one. How
does it do that?

- David Harper