Oldie but goodie here.
Axes have been round for quite a while; after all, what’s simpler than driving a sharp metal edge into a piece of wood? Unlike the wheel however, the tool’s longevity doesn’t mean its design can’t be improved upon. Take the Vipukirves axe pictured above. It helps you split wood more easily by offsetting the center of mass to the side. This way, each time you drive the axe down onto your log, you’ll also generate some rotational torque. This torque, applied to the part of the axe that’s already in the wood, acts as a lever and splits the wood down its fibre, reducing the amount of force needed to accomplish the same results. It’s ingenious and simple, and if the video below is anything to go by, does actually appear to improve on the old design. Sadly, innovation often doesn’t come cheap, and the Vipukirves is no exception. Owning one will set you back €155.74 or about $215, plus €47.26 ($65) in shipping.