Gray code. The reflected binary code (RBC), also known as Gray code after Frank Gray, is a binary numeral system where two successive values differ in only one bit (binary digit). The reflected binary code was originally designed to prevent spurious output from electromechanical switches.
Neural tube defects happen when the neural tube does not close as expected. Anencephaly occurs when the end of the neural tube that would have developed into the brain does not close properly, resulting in the failure of the development of major portions of brain, skull and scalp.
If the posterior neuropore does not close, a spina bifida occurs. If, on the other hand, the closure of the anterior neuropore fails to take place, an anencephaly results. While the neural tube is in the process of closing, cells on the lateral side of the neural plate detach themselves and form the neural crest.