You don't want to tile anything on a small mobile device screen.
Could you elaborate? A 7" tablet's screen is big enough to contain two windows the size of a phone's screen, and a 10" tablet's screen is as big as that of the laptops they were selling from 2009-2012. I have one of those laptops, and I have no problem putting two 80-column text editor windows side by side. The only thing missing from Android is a manifest flag for flexible screen size that would allow this sort of window management. Currently, applications are allowed to assume window size is fixed at install time.