You should see teal underneath the dotted black border below.
There should be exactly two teal-bordered aqua rectangles visible inside the dotted border at all times, with yellow stripes above and below.
As you scroll the element below the teal, aqua, and yellow regions should not move.
However, as you scroll the aqua-and-teal element, a cat surrounded by an orange dotted border should come into view, with its own associated nested scrolling mechanism.
As you scroll the aqua-and-teal element, the cat should move up and down with its border.
As you scroll the numbers inside the orange border, the cat should not move.
The aqua rectangles should be visible inside the dotted orange border.