Different power sockets have different expressions. I had fun thinking up a cute, fun scenario to explain the expressions, involving a tug of war, anger, suprise, a ninja and just messing around making a smiley face.
Available to buy at the following online stores:
You can find the design on t-shirts in most stores, but also on other products e.g. hoodies, mugs, clocks, duvet covers, shower curtains, notebooks etc.