Three is a prominent motif in both written communication and design.
The Rule of Three is consistently used by writers to convey ideas. Alexandre Dumas gave us the three musketeers. Shakespeare's Macbeth tells of three witches, three murderers, and three apparitions. Children's stories regale us with tales of three bears, pigs, blind mice and men in a tub.
The Rule of Thirds is also a principle employed by designers and photographers, involving the division of a canvas into vertical and horizontal thirds. Using these planes to place important elements has been shown to be most pleasing to human preception.