Each section below has three boxes.

- Top - runs on the main thread.
- Middle - runs on the compositor, timing function set on whole animation.
- Bottom - runs on the compositor, timing function set on the first keyframe.

The animations should be identical but start at different times.

This test is successful if the boxes are mostly in sync (there might be a small offset between them).

Start delay 0s (no start delay, should finish first.)
Start delay 3s (starts 3 seconds after page load, should finish last.)