TrafficLights PetriNet Model TrafficLights Extracted from ConceptBase and layed out by Graphviz gy2 gy2 yellow2 yellow2 gy2->yellow2 yr2 yr2 red2 red2 yr2->red2 safe1 safe1 yr2->safe1 rg2 rg2 green2 green2 rg2->green2 gy1 gy1 yellow1 yellow1 gy1->yellow1 yr1 yr1 safe2 safe2 yr1->safe2 red1 red1 yr1->red1 rg1 rg1 green1 green1 rg1->green1 green2->gy2 yellow2->yr2 red2->rg2 safe2->rg2 safe1->rg1 green1->gy1 yellow1->yr1 red1->rg1