To the left are 3 frames from a movie of a simple circuit in operation.  The colored spots are  light emitted by the circuit -- red is more light, blue is less.  These spots are superimposed on a photo of the circuit. Each frame  is 34 trillionths of a second (!).

The image on the right  is a more complicated circuit -- an IBM S/390 microprocessor chip -- in operation. This was taken from the backside of the chip.  Yellow is more light, red is less. This shows how the chip clock propagates to all parts of the chip at the same time. Each frame is 28 trillionths of a second.