We had some good answers last week, but now it's time for another puzzle!
From high in the sky, a pair of aliens observes humans using a bizarre object. Perplexed, one alien turns to the other and says:
"How strange. The Earthling is opening a hole in a sheet of paper and marking it with a line to show the other Earthlings where the hole is. I've never seen anything like it!"
What could these extraterrestrial visitors be talking about?
Remember! You have 3 hints to use if needs be...