{ Petri net generated by APT for net exercise 1.2 net } PLACE s1, s2, s3; MARKING s1 : 1, s2 : 1; TRANSITION t1 CONSUME s1 : 1, s2 : 1; PRODUCE s3 : 1, s1 : 1; TRANSITION t2 CONSUME s3 : 1; PRODUCE s2 : 1; TRANSITION t3 CONSUME s1 : 1; PRODUCE s3 : 1; TRANSITION t4 CONSUME s3 : 1; PRODUCE;