The first sentence makes very clear what the topic is. The unity of the paragraph can be seen in the ease with which one can give it a title, the Ten Hours Bill, and in the fact that every sentence is relevant when tested against that title.
The number of stripes changed frequently until around 1800. Red, white, and blue became the colours of liberty and an inspiration for other revolutionary flags around the world. Effective date: 19 February 1937.