Possibly a strained analogy - but for a very simple system that is Turing-complete there is always Combinatory Logic which only needs two very simple functions (S &amp; K):<p><a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Combinatory_logic" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Combinatory_logic</a>