Using adders, subtracters, comparers, copiers, or multipliers, draw block diagrams for Turing machines that compute the following functions for all positive integers $n$ :

$($a$)f(n)=n(n+2).$

$($b$)f(n)=n^4.$

$($c$)f(n)=2^n.$

$($d$)f(n)=n!.$