Your friend decides to challenge you one day, telling you that, "Hey, here's 12 Steem Dollar coins for you, but wait, one of them is fake. If you can figure out which of the twelve is fake, I will let you keep the 11 real coins and give you one more real coin. However, if you accept the challenge and can't find the fake coin, you'll have to give me 12 Steem Dollars instead.

You, a clever mathematician, thinks the problem should be easy to solve, and asks, "Sure, what's the catch?" To which your friend replies, "the terms of the challenge is that you may only use a scale 3 times to find out which of the twelve coins is fake."

The fake coin could be lighter or heavier than a real coin. You don't know.
You may only use the scale 3 times.
The scale can only be used to determine which side is heavier, lighter, or equal in weight.
There is no magic involved :)