The flight paths of three different groups of bats cross over an open field. The bats’ design follows the P1 symmetry group. When any two flight paths traverse, the symmetry changes from group P1 to P3 because of the flight path intersection (indicated by faint lines). The P1 and P3 symmetry groups are separated by one degree on the wallpaper subgroup relationships graph. I created this piece using only line work with no gray tones.