The initial position and direction of each triangle: randomly uniformly distributed
Implementation
For efficiency, cell lists were used.
The below paper describes dynamics in detail.
Reference
Tamás Vicsek, András Czirók, Eshel Ben-Jacob, Inon Cohen, and Ofer Shochet "Novel Type of Phase Transition in a System of Self-Driven Particles"Phys. Rev. Lett.75, 1226 (1995).