\begin{tikzpicture}

    \node[backtrack] (boxA) at (0, 0) {$<<boxA>>$};
    \node[backtrack] (boxB) [right=1cm of boxA] {$<<boxB>>$};
 
    \node[backtrackeq] (boxAeq) [below=-1pt of boxA] {$=$};
    \node[backtrackeq] (boxBeq) [below=-1pt of boxB] {$=$};

    \node[backtrack] (boxArev) [below=-1pt of boxAeq] {$<<boxArev>>$};
    \node[backtrack] (boxBrev) [below=-1pt of boxBeq] {$<<boxBrev>>$};

    \node(boxAr) at ([yshift=24pt,xshift=5mm]boxA) { };
    \node(boxBl) at ([yshift=24pt,xshift=-5mm]boxB) { };
    \draw [line width=0.4pt,-{Stealth[length=2mm]}] (boxAr)  --node[backtrackstep, above=3.0pt] {$<<stepAB>>$} (boxBl);
    
    \node(boxBrevl) at ([yshift=-24pt,xshift=-5mm]boxBrev) { };
    \node(boxArevr) at ([yshift=-24pt,xshift=5mm]boxArev) { };
    \draw [line width=0.4pt,-{Stealth[length=2mm]}] (boxBrevl)  --node[backtrackstep, below=3.0pt] {$<<stepABrev>>$} (boxArevr);

\end{tikzpicture}



