If I start with a set of consecutive primes, let's say $\{2,3,5,7\}$. Consider $2\times 3\times5\times7+ 1 = 211$. Now, $211$ is prime, so I add it to the set: $\{2,3,5,7,211\}$. If the resulting number is not prime, add the prime divisors of this number which are not in the set.
Just out of curiosity, does this generate all primes for any given starting set? If true, how can you prove that?