\[\begin{array}{l}{Q_1} = \overline a + b \cdot {Q_1}\\{Q_2} = \overline b + a \cdot {Q_2}\end{array}\]
\[\begin{array}{l}{Q_1} = \overline a \cdot (b + {Q_1})\\{Q_2} = \overline b \cdot (a + {Q_2})\end{array}\]
\[\begin{array}{l}Q = s + Q\\\overline Q = r + \overline Q \end{array}\]
\[\begin{array}{l}Q = \overline R \cdot (S + Q)\\\overline Q = \overline S \cdot (R + \overline Q )\end{array}\]