Breaking OUT, imaginary boundaries
Most of us impose too many imaginary boundaries, restrictions, and constraints upon our problems, and hence fail to solve them.
The problem: Draw four straight lines through the nine dots without retracing and without lifting your pen from the paper.
The key to the solution is, of course, that the imaginary boundaries formed by the dots need not be observed. Once freed from this restriction, you will find the solution easy.
Researchers at Stanford University have come up with an even more interesting solution to this puzzle. One subject realised that it wasn't necessary to draw four lines through the centers of the dots; the problem can be solved with only three lines. Lets give that a go.