Click the flag and it generates prime numbers (in order). If you don't know what a prime number is, then it is basically a whole number 'n' that does not have any factors (numbers that you can divide 'n' by with no remainder) except for 1 and itself (excluding 1 for some reason). For example, 27 is not a prime number because you can do 27 divided by 3 (9) with no remainder however, 29 is a prime number because there is no number that you can divide 29 by with no remainder (except 1 and 29)
I just made this for fun I plan to make this faster later on.