With its large display and pro-quality apps, only curmudgeons and those in denial still believe the iPad incapable of being used for productive creative projects. But the iPhone’s a trickier sell.

As the resident bad cartoonist at TidBITS (see “iPad Tools for Bad Cartoonists (and Good Ones, Too),” 29 November 2012), I am occasionally called upon to look at professional quality drawing tools to ...