Patents are shown as boxes arranged in time on the horizontal axis starting with the oldest on the left. The left edge of each Patent Box is the Patent Issue Date. The blue "tail" on each Patent Box shows the Patent Application Filing Date.
The lines connecting the Patent Boxes are the patent citation references- i.e. the patent to the right (forward in time) cites the patent to the left (backward in time) as Prior Art.
The number of Forward Citations and Backward Citations for a given patent is displayed in the parenthesis in the Patent Box for that patent.