[danielf]

Originally Posted by zoombini

The brain teaser is worded as:



Now I can see that this is real easy if you are allowed to use curved lines.
(as in the 2nd image)

However, what if you MUST use straight ones?
We thikn that the question is just badly worded but should be straight lines only. Otherwise it ws too easy & the question is usually hard.

I think curved lines must be allowed. If it was straight lines, then it wouldn't make sense that they can touch only once. Two straight lines that touch (and don't cross) are overlapping lines.