In 222 shell - horizontal symmetry you also see how exclusion lines that belong to a prime numbers, and square’s of
prime numbers, create uncluttered corridors.
The largest of these is the corridor of the 1 shell at 0 radians, then
the 2 shell at pi radians. The 2 shell
actually goes off in two directions because it shares one of those with the 1
shell. They are half the width of the 1
shell’s corridor. The three shell also
shares one corridor with the 1 shell, leaving 2 left over at 2×pi/3 radians. The 4 Shell shares a corridor with the 1 and
2 shells, so is not prime, it belongs to the 2 shell. The final corridors shown on the diagram are
the 5 corridors, whose locations in mirrored in the x-axis.