How to get better at solving puzzles

I've been reading a 1978 book called The Art of Problem Solving, by Russell L. Ackoff. (Used copies sell for $7 including shipping on Amazon). At the beginning of the book, Ackoff tells about the time his school-age daughter came home with a familiar puzzle. On a piece of paper, there are nine dots arranged in three rows of three, like this:

The challenge is to put a pen on the paper and, without lifting the pen, draw four straight lines that go through all nine dots. You probably remember this puzzle, because it's been around for a long time. Ackoff remembered it, too, but he'd forgotten the solution. But he came up with another way to solve it. He folded the paper so two rows of dots touchedeach other and used a felt pen to draw through both rows with one stroke. Then he unfolded the paper and drew two more lines to cover the rest of the dots.

When Ackoff's daughter went to school the next day, she started to show the teacher the solution her father came up with. As soon as she began folding the paper, the teacher stopped her and said she was not allowed to fold the paper, even though the instructions didn't say she couldn't.

"This is how creativity is suppressed, although usually not so overtly," writes Ackoff. "The teacher made it clear to her class that the objective of the assignment was not to find a solution to the problem, but to find the solution she knew and could pretend to have discovered on her own. Read the rest