A laptop power supply. It's a circular 4-pin connector https://digipres.club/system/media_attachments/files/113/047/628/388/416/845/original/79b32ab9a36e6bbd.jpeg
HOT TAKE: if you design a laptop with a power supply that looks like this, you should go to jail.Laptops should be powered by TWO WIRES and the voltage, amperage, and polarity should be WRITTEN ON THE BOTTOM, UNDER PENALTY OF LAW