$(8$ points$)$ Multiplexer: A $22$ crossbar switch has $2$ inputs and $2$ outputs and is used to connect any

input to any output. If $s=0,$ the crossbar shown below connects $x1$ to $y1$ and $x2$ to $y2,$ while if $s=1,$ the

crossbar connects $x1$ to $y2$ and $x2$ to $y1.$ Please implement the crossbar using $2-$to$-1$ multiplexers.