Datatype constructors 3.12.1.
Concatenation is defined using extent as the size of the concatenated copies.
Example Let oldtype have type map with extent 16, and let . In general, assume that the type map of oldtype is with extent ex . Each block is obtained by concatenating the same number of copies of the old datatype. The spacing between blocks is a multiple of the extent of the old datatype. Let bl be the blocklength.