T1 T2 T3 A marble is dropped at A or B. Levers xi, 72, and r3 cause the marble to fall either to the left or to the right. whenever a marble encounters a lever, it causes the lever to reverse after the marble passes, so the next marble will take the opposite branch. Model this toy as a finite automaton. An input to the atomaton is a string over the alphabet A, B, which represents a sequence of marbles being dropped into the toy. The toy is initially in the configuration above before any marbles are dropped (so that the first ball will exit at C regardless of where it is dropped). Say that a sequence of marble drops is accepted exactly in the case that if one additional marble were to be dropped in, it would go out through D regardless of where it was dropped T1 T2 T3 A marble is dropped at A or B. Levers xi, 72, and r3 cause the marble to fall either to the left or to the right. whenever a marble encounters a lever, it causes the lever to reverse after the marble passes, so the next marble will take the opposite branch. Model this toy as a finite automaton. An input to the atomaton is a string over the alphabet A, B, which represents a sequence of marbles being dropped into the toy. The toy is initially in the configuration above before any marbles are dropped (so that the first ball will exit at C regardless of where it is dropped). Say that a sequence of marble drops is accepted exactly in the case that if one additional marble were to be dropped in, it would go out through D regardless of where it was dropped