Take a look at the dial clock

[powolny17]

Take a look at the dial clock
By dropping the exceptional two prime numbers, i.e. 2 and 3 (I personally treat 1 as a prime number),
then each prime number will be on the radius of 1 hour, 5 hours, 7 hours, 11 hours - 13 hours, 17 hours, 19 hours, 23 hours - 25 hours (not prime), 29 hours, 31 hours etc.

This clock can be collapsed into a 6-hour dial. Then all primes except 2,3 are on radius 1 and 5.
So every prime number is in the field 6n + -1.
Of course, there are also non-prime numbers as shown above 25.
But each, except 2 and 3 (I already wrote about 1), is on these rays.

Interestingly, when you put this 6-hour dial so that 0 is on the x axis, the axes 1 and 5 have cos (angle) = 1/2 (angle = 60 degrees). As in non-trivial zeros in the Riemann theorem.

Marcin
(sorry, i can't speak english, i use the translator)