Drones help people explore dangerous, inaccessible areas. For example, they study the territories affected by natural disasters. However, these gadgets have a significant minus – they are usually very wide and can not always squeeze into narrow openings. To solve this problem, engineers from Switzerland developed an experimental quadrocopter. The device, folding, can overcome fairly narrow passages in this form. In the basic layout, the sleeve of the device with the rotors located on them has a traditional configuration: X-shaped, if you look at it from above. If the drone is required to squeeze into a narrow vertical aperture, its rear arms are pulled back and the front ones are pulled forward. In this case, the gadget becomes much narrower. There are other options for folding the hands of the device. If the upcoming opening of the device is horizontal, all of his hands can fold right away, and the drone becomes significantly smaller. Each of the four “hands” of the device is separately controlled by an independent servomotor. It, in turn, is controlled by a special microprocessor. For each rotor, the thrust is automatically adjusted. This ensures the flight stability of the device, regardless of configuration.