Still images are rapidly displayed in sequence
If the positions of shapes on the images change,human perception is that the shapes move
Need 10 frames per second to give smoothflicker-free motion...
…but more are needed in practice, where there are “blanks” in between images
– cine projectors use one or more “blades” to cover the projector for a small period of time whilst the film advances
Cine films generally have 24 frames per second