Locally decodable codes can also be composed with one anotherconcatenated, where a message is encoded first using one scheme, and the resulting codeword is encoded again using a different scheme. (Note that, in this context, [[concatenation]] is the term used by scholars to refer to what is usually called [[function composition|composition]]; see <ref name=AppCodingTheory/>). This might be useful if, for example, the first code has some desirable properties with respect to rate, but it has some undesirable property, such as producing a codeword over a non-binary alphabet. The second code can then transform the result of the first encoding over a non-binary alphabet to a binary alphabet. The final encoding is still locally decodable, and requires additional steps to decode both layers of encoding.<ref>Section 19.4.3 of {{Cite book
