Say you have a @keyframe animation that animates an element all the way across the screen. From off the left edge to off the right edge. You apply it to multiple elements. But you don't want all the elements to start at the same exact position.
You can change the animation-delay so that they start at different times, but they will still all start at the same place.
Fortunately, there is a way.
The trick is to use negativeanimation-delay. That will begin an animation right away, but as if part of the animation has run already.