For those of you who pride yourselves in your 3d visualization skills, try this.
Imagine a paper Mobius strip that has had a pencil line drawn along its length until the pencil line connects with its beginning. Then imagine taking a pair of scissors and cutting the strip along the pencil line. What will that produce?
Think it through and then try it to see if you visualized it correctly.
There is a next step, but I can't reveal that without spoiling the answer to the first step.
Imagine a paper Mobius strip that has had a pencil line drawn along its length until the pencil line connects with its beginning. Then imagine taking a pair of scissors and cutting the strip along the pencil line. What will that produce?
Think it through and then try it to see if you visualized it correctly.
There is a next step, but I can't reveal that without spoiling the answer to the first step.