There are some workarounds to this problem, but not many of them are as smooth an effortless as this one which uses erasable pen ink to add colors to the filament on the fly. Erasable pen ink is a ...

You've definitely used dry-erase markers to mark up a whiteboard in a classroom or at the office—they’re so ubiquitous, they’re even replicated in apps that allow you to keep a whiteboard in ...