\left(\left\{\begin{array}{ccc}\begin{array}{c} \Qcircuit@C=1em @R=.7em{
& & \gate{CONTROL~\mbox{on}~\left\{t + 1\right\}} & \qw
} \end{array} \textrm{ if } {_{-}b} = 1 \\ \begin{array}{c} \Qcircuit@C=1em @R=.7em{
& & \qw & \qw
} \end{array} \textrm{ if } {_{-}b} \neq 1\end{array}\right.., \left\{\begin{array}{ccc}\begin{array}{c} \Qcircuit@C=1em @R=.7em{
& & \gate{CONTROL~\mbox{on}~\left\{t + 1\right\}} & \qw
} \end{array} \textrm{ if } {_{-}b} = 2 \\ \begin{array}{c} \Qcircuit@C=1em @R=.7em{
& & \qw & \qw
} \end{array} \textrm{ if } {_{-}b} \neq 2\end{array}\right.., \ldots, \left\{\begin{array}{ccc}\begin{array}{c} \Qcircuit@C=1em @R=.7em{
& & \gate{CONTROL~\mbox{on}~\left\{t + 1\right\}} & \qw
} \end{array} \textrm{ if } {_{-}b} = t \\ \begin{array}{c} \Qcircuit@C=1em @R=.7em{
& & \qw & \qw
} \end{array} \textrm{ if } {_{-}b} \neq t\end{array}\right..,\begin{array}{c} \Qcircuit@C=1em @R=.7em{
& & \gate{U_{{_{-}b}}~\mbox{part}~1~\mbox{on}~\{t + 1~\ldotp \ldotp~t + m\}} & \qw
} \end{array}, \begin{array}{c} \Qcircuit@C=1em @R=.7em{
& & \gate{U_{{_{-}b}}~\mbox{part}~2~\mbox{on}~\{t + 1~\ldotp \ldotp~t + m\}} & \qw
} \end{array}, \ldots, \begin{array}{c} \Qcircuit@C=1em @R=.7em{
& & \gate{U_{{_{-}b}}~\mbox{part}~m~\mbox{on}~\{t + 1~\ldotp \ldotp~t + m\}} & \qw
} \end{array}\right)