Can such a house of cards exist? The number of cards increases level by level in a constant sequence. If you want to prove the puzzle’s answer, you have to show that 100 is a term in this sequence.

The most common picture puzzle challenges involve finding a mistake, solving a code, or spotting the hidden object in the ...

The "spot the difference" game is a popular type of puzzle in which two similar-looking images will be placed side by side.

Quiz is untimed. Quiz plays in practice mode will not be counted towards challenge completion or badge progress.