The Constrained Ball by Giha Woo is the answer to my prayers. As a kid who always hated having to pull out my ruler to draw a straight line, this trusty device is fitted to my liking. Once attached to the pen, this piece can help you draw straight lines with ease while measuring the distance of the drawn line.

Lazy kids everywhere rejoice because the Constrained Ball by Giha Woo will lose your need for a ruler.