Just click the green flag! You can find what it is exactly in the Notes and Credits.
Thanks to David J Malan for the idea, inspiration and showing how it works. An Integer Overflow is the condition that occurs when the result of an arithmetic operation, such as multiplication or addition, exceeds the maximum size of the integer type used to store it. In computer programming, an integer overflow occurs when an arithmetic operation attempts to create a numeric value that is outside of the range that can be represented with a given number of digits – either higher than the maximum or lower than the minimum representable value. That is what has happened in this project. The project keeps doubling 2 and makes the value obtained lesser than 2; and later reaches infinity.