Hardware fun with a RB2011UiAS-2HnD-IN (this is a joke)
The other day, I was testing a 10 port RB2011UiAS-2HnD-IN (the red mikrotik).
I had the wall power supply connected to the power jack in the back. I then connected Ether1 to Ether10 (Ether1 is also a POE power in port -and- Ether10 is a POE power out port). Anyways, I then disconnected the power supply from the back of the Mikrotik. Now the Mikrotik was only running on power going into the Ether1 POE port. Well - it worked and runs well.
The Ether10 power out (POE power out) is able to power the Ether1 (POE power in) port on the same Mikrotik.
The problem, If I reboot the Mikrotik (no power supply connected on back with Ether1 connected to Ether10), the Mikrotik will shutdown and loose power. I then need to reconnect the rear power supply again to get it started again before I can remove the rear power connector again.
((( This type of power connection gives me an idea - I wonder if I can get free electricity for my house if I connect an electric motor to an electric generator )))
If you for a moment believed any of this post - then lol , this is impossible. But - I bet I made you smile 
BTW - Have you ever plugged a UPS into itself ? Trust me , it does not like itself !!!
North Idaho Tom Jones