How to get better at solving puzzles


Originally published at:


I’m solving a puzzle right now.


This puzzle is on the cover of the book that popularized “think outside the box.” Took the guy’s class several times as part of work training.
My solution was to use a bigger pen. Only need one line if it’s big enough.


I hope this isn’t too much of a hint:

Think backwards


i only watch youtube/twitch videos/streams of other people doing puzzles


For the nine-dot puzzle, if the dots are large enough, you can use three angled lines in a Z to hit all nine. For the missile problem, ignore the starting position. You should be able to work the rest out in your head, even if you’re not a brilliant mathematician like Gardner.


The classic is of course the “How to tell the height of a building using a barometer.”
Creative answers include

  • Measuring the length of the shadow of the barometer and comparing it to the length of the shadow of the building
  • Dropping it off the roof and timing until it lands
  • Swinging it on a string as a pendulum, and measuring the difference in period at the top and bottom of the building

and my favorite

  • Knocking on the door of the building superintendent and saying, “I’ll give you this fine barometer if you’ll tell me how tall the building is.”


The answer to the Colliding Missiles problem, without additional context, is the same as the answer to many such problems. It depends.

It depends partially, for example, on whether there’s anything between the missiles or not. For example, if they’re flying “directly towards each other” in the context of space, but the Earth is in the way, at an initial separation distance of 1317 miles, the curvature of the planet suggests that they would both plow into the planet well before being a minute apart.


500 miles


wrong. 500 miles


I feel like this is somewhat unfair to the teacher. A key thing for (good) puzzles is that they are constrained enough that there is something non-obvious to solve. It wouldn’t be clear to the teacher that the puzzle is still interesting if you can fold. (You can get all the points in exactly the same place by folds, after all.)


This is exactly why I hate “lateral thinking” puzzles. They always want a specific creative solution.

There is a famous puzzle I’ve always hated about having three light switches in one room and three light bulbs in another room. My first solution was to ask someone for help, but I was told that wasn’t allowed, despite that being a very good solution to that problem in the real world and the puzzle containing no hints that this would be impossible. And the “real” solution assumes incandescent bulbs, which is hardly a fair assumption, even at the time it was first presented to me.


I would walk that.


This calls for:


Divide the Miles/Hour values by 60 to get Miles/Minute, then sum them


Or add first and divide second for a little easier route.


9,000 miles per hour and the other at 21,000

I love puzzles. It doesn’t matter how far apart they start. At time of collision they are zero miles apart. One minute before collision they are 9000/60 + 21000/60 miles apart, or 150+350 or 500 miles apart.


The second number is 21,000 not 12,000…


Here’s my uncreative solution to the dots problem: put down the pen and type this:


I don’t view the last example as a “lateral thinking problem” or a “puzzle”. I think it’s just an algebra problem with an extraneous piece of information.