+This works because the semaphore queue is FIFO. So the first one locks the
+semaphore to update the global variable, the second task also wants to do this
+but he has to wait in the queue and will be the next in line. After the first
+task releases the semaphore the second task locks it and the first task has to
+line up in the queue again. This goes on, tasks taking turns, till the tasks
+are finished.