The Collatz conjecture (also known as the 3x+1 problem) is a maths problem that has stumped all mathematicians that have tried solving this. The problem states that no matter what number you start with, if you follow a set of rules, you will always end up with the sequence 4,2,1. The rules are as follows: If the number is even, half it, and if the number is odd, you multiply it by 3 and add 1. You keep doing this to the outputs until you reach the earlier stated sequence. If you hover over a cross, it will show the number it represents. Try 27!
