All text is defined in terms of character set code tables.
Each plane is itself arranged in 256 rows of 256 characters. 32 bit combinations were reserved per page in this schema for control character allocation. In the UCS world, only the first row of 256 characters reserves 64 bit combinations for control characters. These characters are not to be used as part of text data. Composite characters are characters that are composed by a base character that is modified by superimposing it with one or more additional characters.