spoilers Show more
In the first you can see the built-in pulse generator connected to each of the 4 inputs in turn. They don't all happen at the same time, because of the slight delay introduced by the cable length between each input.
In the second screenshot I turned off the termination on the 4th channel and grounded the input, so you can see the pulse actually reflect off the input and back up to channels 3, 2 and 1.
How's that for a demonstration of physics? :)