\begin{figure}[H]
\centering
\begin{circuitikz}\draw
(0.5,0.0) to[ospst] (2,0.0)

(4,1) node[and port] (myand) {}
(6,-1) node[nor port] (mynor) {}
(8,-1) node[xor port] (myxor) {}
(10,0) node[or port] (myor) {}

(2,2.0) -| (myand.in 1)
(2,0.0) -| (myand.in 2)


(myand.out) -| (mynor.in 1)
(2, 0 ) -| ( 4, -1 ) (4, -1) -| (5.08, -1 )
(2, -2) -| (mynor.in 2)


(2,2.0) -| (myxor.in 1)
(mynor.out) -| (myxor.in 2)

(2,2.0) -| (myor.in 1)
(myand.out) -| (8, 0) (8, 0) -| (9.08, 0)
(myxor.out) -| (myor.in 2)

(myor.out) -| ( 10.5, 0 )
;


\draw( 0, -1.5 ) rectangle( 2, -2.5 );
\draw node[align=center] at (1,-2.0){Clock\\Period=5};

\draw( 0, 1.5 ) rectangle( 2, 2.5 );
\draw node[align=center] at (1,2.0){Clock\\Period=5};

\draw( 0, -0.5 ) rectangle( 2, 0.5 );


\draw( 3.3, -2 ) node[cross=5pt, red, thick, align=left](clock1){};
\draw( 2.3,  2 ) node[cross=5pt, red, thick, align=left](clock2){};

\draw( 10.2, 0 ) node[cross=5pt, red, thick, align=left](output){};

\draw( 4, -3.2 ) node[cross=5pt, red, thick, align=left](key){};
\draw (5.6, -3.23 )node[align=center]{Monitoring Point};

\end{circuitikz} 
\caption{$2^{nd}$ Example Logic Circuit}
\label{fig:example2}
\end{figure}
