% NOT-gate NORTH
\newsavebox{\notn}
\savebox{\notn}(6,10){
\begin{picture}(6,10)
\put(3,0){\line(0,1){2}}    % input
\put(0,2){\line(1,0){6}}
\put(3,7.75){\circle{1.5}}
\put(0,2){\line(3,5){3}}
\put(3,7){\line(3,-5){3}}
\put(3,8.5){\line(0,1){1.5}}
\end{picture}
}