Updated: Aug 26, 2019
Mining bitcoin on solar power with zero energy costs.
Sunlight hits the solar panel(s) and is sent to the charge controller, from there it powers the Raspberry Pi computer with mining software operating the ASIC miners that are plugged into the USB hub, which is glowing blue. This process is by technicality "printing money". Once exchanged into USD from Bitcoin, and withdrawn from any Bitcoin ATM, sunlight has been converted into cash.