For small viewports there can be situations where the float layout breaks:
The farer you go down the timeline the nearer the dots for each book box will come: This happens because of different heights of the book boxes, because the book covers aren't all the same height on each side of the timeline. This may also happen on smaller screens and different title lengths of the books, when the book title wrap into more than 2 lines on one side, but not on the other.
The same problem can lead to wrong floats when the book on the left side needs much more height than the one on the right side.
For small viewports there can be situations where the float layout breaks: