Task: tape (or glue) a paper strip into a ring and draw a line down the center of both sides.
Rules: draw the line lengthwise on both the inside and outside of the ring without breaking the line or lifting the pen from the paper.
Think it’s impossible? Give it a try!
You will need: a piece of paper, scissors, a pen (or pencil) and tape (or glue).
Cut a strip of paper and attach tape to one end.
Hint: before attaching the two ends, turn one end over so it faces inside out.
Attach the ends, forming a ring.
Take the pen and confidently draw the line until it meets up with itself!
You’ve done it! You’ve drawn an unbroken line along both sides of the ring. Now you can challenge your friends to solve the puzzle, but of course don’t give them the hint. And that’s not all!
Try a different approach. Make a bet with your friends that they can’t draw a continuous line with one pen on the outside of the ring, and with a different pen on the inside. Make the ring as above, but use a long paper strip so no one notices how the ends are attached. “Easy!” your friends will say, agreeing to the bet. But to their surprise, they’ll discover that they’ve drawn the line with one pen on both sides at once–and lost the bet!