variable logic gate

The logic gate type MC 14530 (and its equivalents) is not used very much. This `dual, five-input majority gate` is, however, intriguing. Amongst other things, it can be used as a `variable logic gate` as described here: by inter-connecting some of its inputs, a logic gate is obtained that will give various logic functions depending on the logic level at two `control inputs`. This can be useful in education, as well as in micro-computers!