Lenovo ThinkPad Battery Charging Bug, ThinkPad is a “Perpetual Motion” Machine?

If you use the USB cable to connect the standard USB port and the micro USB port of Lenovo ThinkPad at the same time, the Android system will prompt “charging”, your ThinkPad is charging battery! LoL, is that means ThinkPad can be a “Perpetual motion” machine? “Perpetual motion” machine is a machine which can “self-sufficiency” working, it is a concept in the physical world.

Just for fun, it is just a battery charging bug, but we don’t know it is software bug or hardware design bug, but many Android Tablets have this two USB ports design, are those Android tablets all have this funny bug?