Mutual Exclusion Demonstration
The program uses a semaphore to ensure that it is not possible for threads
to enter their critical sections at the same time. The critical section is
represented by a light blue (cyan) colour. To execute in this region, a thread must
have acquired mutual exclusion by executing a down() operation on the semaphore
Mutex. The length of time each thread spends in its critical section may be adjusted
using the slider control. Further to the right increases this time. The adjustment takes effect at
the beginning of each revolution.