A few years ago I heard about the Tim Tang Test for the first time. It is a series of puzzles hosted on the internet. The entire test has never been passed. I spent a few hours working on it and advanced through eight levels. But then I forgot about it.
Recently the test came to mind, so I decided to see if it was still in operation. The website changed considerably, but it is hosted here.
The entire test is different than the one I had seen before. It is a bit more polished, and the puzzles in levels 1-6 have been changed. I solved the first 5, and I think I figured out the logic of the sixth, now it’s a matter of coming up with the right answer. Some of these puzzles seem impossible at first, but once you manage to crack the theme or code it seems very obvious.
If you like puzzles you should check out this website. No one has completed the test yet (it seems likely no one ever will).
I’ll warn you that it can be a bit addicting. . .