I just tweeted a very interesting two truths and a lie:
- All even numbers greater than 2 are sums of primes
- The logical conjunction of the above two
I'll leave the solution to the reader. It occurred to me while lying in bed, however, that it should be possible to make a list such that any of the three can be the lie. After a little thought and some trial and error, the following fits the bill:
- One of the following two statements is false
- One of the other two statements is false
- One of the previous two statements is false
Simple, but it works. Neat.
This reminds me of the riddle in Inside Man:
Which weighs more: all the trains that pass through Grand Central Station [in NYC] in a year - or the trees cut down to print all U.S. currency in circulation? Here's a hint: It's a trick question.
Once again, I leave the solution as an exercise to the reader... or you can watch the movie.
EDIT: here are a few more humorous Two Truths and A Lie's I came up with:
- Water is wet
- Fire is hot
- The cake
"well, obviously, the cake is a lie."
- You think this one is true
- You think the last one is probably the lie
- You're not sure anymore
- Either you won't answer, or you'll answer correctly
- Either you won't answer, or you'll answer incorrectly
- You will answer
Interestingly, it's possible to correctly answer this last one. You can figure out how.