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.