This shows the trails of some globules of colour. Several bodies eject them as they move. Each of these bodies belongs to one of four castes according to the colour of the globules it ejects.
- caste 1 – bodies that eject white globules
- caste 2 – bodies that eject blue globules
- caste 3 – bodies that eject tawny globules
- caste 4 – bodies that ejects greenish globules
Each caste, in turn, belongs to one of two pairs:
- pair 1 – castes 1 and 4 or
- pair 2 – castes 2 and 3.
Each body and each globule targets a particular caste. Bodies target the other member of the pair to which their own caste belongs. Globules target the other member of the pair to which the caste of the body that ejected them belongs. As it moves, each body or globule accelerates with a constant magnitude of acceleration towards the closest body belonging to the caste it targets. Each globule fades as it moves.