Rotating Billboard Display

Problem Statement: Design a $2-$bit counter using an FSM to drive the select lines $($S$1,$ S$0)$

of a $1-$to$-4$ demultiplexer. The demux controls four billboard sections $($D$0,$ D$1,$ D$2,$ D$3)$ to

display different advertisements:

$$ D$0$: Section $1$

$$ D$1$: Section $2$

$$ D$2$: Section $3$

$$ D$3$: Section $4$

The sections illuminate sequentially, and the sequence restarts after all sections have

been displayed. The clock determines the rotation speed of the display.