A lot of the pattern comes down to primes being relatively prime to smaller numbers, which means, for example, they're 1 modulo 2, 1 or 2 modulo 3, etc. You combine these together and find that, for example, they're all (aside from 2 or 3) going to be 1 or 5 modulo 6. Which would mean that if you lined all the numbers up in rows of 6, all primes (aside from 2 or 3) would be in the first or fifth columns.
So properties can give them a "shape", but they won't identify them.
Good question. The first of the odd primes up to 7 occur as the most frequent factors, other than 2. So 3,5,7 are most often reoccurring. Because of the patterns they illustrate especially when modulating the columns it seemed to make sense.
While all of that is true, the original concept for the project was based off the Sieve of Eratosthenes.
Hehe I asked because time ago I implemented something similar (using console though) and by instinct I was doing the same, coloring numbers based on divisors to see patterns, and primes, but just when I wanted to get some conclusion out that, I had to stop and do something else, so it kinda remained in my brain as something I had to finish to consciously understand.
Thanks for explaining then, so what we did is a Sieve of Eratosthenes... But I have to admit that I also coded it to see which particular patterns (if any) primes were drawing on screen.. :)
So properties can give them a "shape", but they won't identify them.