9 dots one line solution
Here it is:
If you didn’t get to this immediately, it was because you made another assumption that wasn’t given in the problem. You were told that the nine dots were on paper, but not that the paper had to remain flat.
So the moral of the story is…
Our attempts to find solutions to problems are constantly hampered by the introduction of assumptions about what is possible or allowed and what is not, assumptions which come from our unconscious minds and not from the problem as it presents itself. The solution, invisible at first, is obvious once we have seen it.
And so how to we get better at seeing the obvious?
There are two ways:
One, we can practice noticing the assumptions we make, and challenging them. This is easily said, but less easily done, particularly when those assumptions are shared by the industry in which we have spent our entire careers.
Two – and this is probably the better course in most cases – talk to someone who isn’t from your world, who doesn’t need to spot and challenge the unwarranted assumptions because they never made them in the first place.