It’s not about how hard you work, but how smart. From the author:

“Here’s an experiment I did with my self-propelled mower. It’s cutting most of the back yard (a large circle) by wrapping a rope around a couple of stakes. The video is played at 4x speed. Yes, we have a lot of weeds, and yes, I need to grease the wheels. Also, this is dangerous, so kludge at your own risk.”

And there you go. Who needs an expensive lawn mowing robot? Video of lawn mowing robot also embedded.