Existing comment:
In the 19th century, stamps were bisected -- horizontally, vertically, or diagonally -- to complete a particular rate. They were also occasionally cut in thirds (trisects) or quarters (quatrisects). By the 20th century, the need for this practice had disappeared in the US, but some collectors have enjoyed trying to pass envelopes with bisected postage through the mail. On occasion, they succeeded. Today, it's illegal to cut, deface, or even overlap stamps on your mail.
Fractional stamps are also a way to complete a rate, and the US has issued several fractional denominations. Most of these paid concessionary rates for third-class bulk and non-profit mailings. |