Paper × 841 mm). A1 is half the size of a sheet of A0 (i.e., 594 mm × 841 mm), such that two sheets of A1 placed side by side are equal to one sheet of A0. A2 is half the size of a sheet of A1, and so forth. Common sizes used in the office and the home are A4 and A3 (A3 is the size of two A4 sheets). The density of paper ranges from for tissue paper to for some speciality paper. Printing paper is about . Paper may be classified into seven categories: Some paper types include:
How many angels can dance on the head of a pin? Suite Part II: Let It Grow", a song from the 1973 Grateful Dead album Wake of the Flood, includes the line "As well to count the angels dancing on a pin." In the comic book "The Crow" by James O'Barr, the main character asks this question to one of his victims before killing them, answering himself, "Depends on the tune". The song "Velodrome" from Minnesota rapper Dessa's 2018 album Chime, references this question in the first verse asking, "Aquinas, call on me/ How many angels on the/ Head of your pin?" How many angels can dance on the head of