The paper Gravitational Experiments with a Cylindrical Galaxy (1967) describes a collisionless computer model used to perform gravitational experiments with a two-dimensional galaxy. The motion of 2000 rods of mass is computed and displayed as movies. They show the types of galactic structure that can arise from purely gravitational effects. A galaxy with insufficient rotation to balance gravitational attraction is seen to collapse and form filamentary condensations, then to change through structures similar to the spirals and barred spirals, and finally to settle down to a cylindrical form reminiscent of an elliptical galaxy.
The actual film is 16 frames/sec. The paper has a frame every 4 secs:
There is an excerpt from the film on the Chilton website.