Take a look at this image. It's an incredibly meaningful image for Australia. Why? Because it was drawn by Australian Aboriginal inventor and writer David Unaipon, a man known for incredible inventions. What you don't realise is that you see this genius almost every day (depending on your means): he's on the Australian $50 note.
Unaipon is being celebrated today for his birthday in a Google Doodle depicting his technical drawing for a new type of shears. This new design allowed shearers to move in straight lines while using the tools -- an innovation that changed the shearing industry.
His other inventions included a pre-World War II drawing of a helicopter based on the same principle as the Boomerang. Unaipon was born on this day in 1872 and he died in 1967. [Google]