One possibility:

\documentclass{article}
\usepackage{circuitikz}

\begin{document}

\begin{circuitikz} 
\draw
  (0,2) node[nand port] (nand4) {}
  (2,3) node[nand port] (nand3) {}
  (4,2) node[nand port] (nand2) {}
  (0,0) node[nand port] (nand1) {}
  (nand1.out) |- (nand2.in 2)
  (nand4.out) |- (nand3.in 2)
  (nand3.out) |- (nand2.in 1)
  ;
\draw 
    ([xshift=-1cm]nand1.in 1) 
      coordinate (aux) node[left] {$c$} to[short,*-] 
    (nand1.in 1);
\draw 
    ([xshift=-1cm]nand1.in 2) 
        node[left] {$d$} to[short,*-] 
    (nand1.in 2);
\draw 
    (aux|-nand3.in 1) 
        node[left] {$a$} to[short,*-] 
    (nand3.in 1);
\draw
  (nand4.in 1) -- coordinate (middle) (nand4.in 2);
\draw 
    (aux|-middle) 
        node[left] {$b$} to[short,*-] 
    (middle);
\end{circuitikz}

\end{document}




Digital circuits
I am looking for very simple bash script that would allow me to launch a process a few times. What's essential to me is that after the processes terminate, everything will clean up automatically.

Intended usage:

bash multiplerun.sh 5 executable.sh parameters_to_executable


I could probably write it myself, but it would take me so long that I've decided to ask experts; I'm very little skilled at using *ix systems.

EDIT: Oh, and I forgot to add that I want to run them in parallel - running them one after another is pretty straightforward.
