lecture : (process)
lecture.x : bool lecture.x = 0
lecture.B : chan(bool<>) lecture.B = (0) [empty]
	0	0	2	null
	10	1	1	
lecture.B : chan(bool<>) lecture.B = (0) [empty]
	20	3	1	lecture.B?(lecture.x)
lecture.B : chan(bool<>) lecture.B = (0) [recvd]
	20	2	1	lecture.B!(false)
lecture.B : chan(bool<>) lecture.B = (0) [empty]
	30	2	1	lecture.B!(false)
lecture.B : chan(bool<>) lecture.B = (0) [sent]
	30	3	1	lecture.B?(lecture.x)
lecture.B : chan(bool<>) lecture.B = (0) [empty]
lecture.x : bool lecture.x = 0
