In-hand manipulation is one of the things near the top of a very, very, very long list of things that humans do without thinking that are extraordinarily difficult for robots. It’s the act of repositioning an object with one hand, usually with your fingers—you do it whenever you pick up a pen, for example, to switch from a “picking up” grasp to a “writing something” grasp. Next time you do this, pay attention to the intricate, coordinated motion that happens, and ask yourself just how in the world you could honestly expect a robot to do something similar.

And yet, robots are learning to do such things. For example, OpenAI recently taught a five-fingered hand to manipulate a cube, which is great, if you have a lot of patience and/or computing resources, and the budget for a fancy hand and stuff. For those of us without wealthy (and occasionally eccentric) patrons, a conventional gripper is a more realistic option, and researchers from Yale University’s GRAB Lab have developed a two-finger design with a clever variable-friction system that can do in-hand manipulation at a fraction of the cost.