  The quantum error correction theory is as a rule formulated in a rather
convoluted way, in comparison to classical algebraic theory. This work revisits
the error correction in a noisy quantum channel so as to make it intelligible
to engineers. An illustrative example is presented of a naive perfect quantum
code (Hamming-like code) with five-qubits for transmitting a single qubit of
information. Also the (9,1)-Shor codes is addressed.
