Titled the OO for the two circular discs at one end of the ruler, Snezana Jeremic’s piece of stationery is capable of measuring linear as well as non-linear surfaces, up to a stunning 99.9 centimeters! Using a clever gear system and two marked rolling-discs, the OO ruler can be rolled on surfaces, with a set of windows depicting the measurement based on how much the discs roll. The lower roller covers the millimeters, while the upper takes care of the centimeters, resetting every 100 centimeters, or one meter. Perfect for rolling down surfaces, the OO helps capture linear as well as non-linear measurements, while its straight-edge scale can be used as a conventional ruler too. Rather nifty, right? My only concern is needing to reset the roller-ruler to 0 every time you want to take a measurement from scratch! Designer: Snezana Jeremic (Nemo)