Run wire from battery to remote light bulb or electromagnet (made by winding wire around iron nail) to transmit an on/off signal (electromagnet will attract other metal when on).
(Run wire from battery to remote light bulb or electromagnet; made; ) (electromagnet; will attract; other metal; T:when on)
Run wire from battery to remote light bulb or electromagnet electromagnet
made will attract
other metal T:when on