A set of two or more characters designed together. Ligatures were widely used in metal-type printing presses, created by carving the character set into a single block. They are used to help solve spacing problems where certain letter pairs are uncomfortably close or crash. With the advent of computer typesetting, ligatures fell out of use until recently, where many fonts now include a large selection of ligatures. By using ligatures, the text is more legible and has a better flow for the reader. However, some ligatures can look like entirely different characters, creating a potential confusion for the reader. Examples of ligatures include: ff, fi, Th and st.