The images above show a model graph and the geometry it creates: a clock. The image on the left shows a model graph with numbered nodes. The numbers show the order of execution of the nodes in the model graph. Normally, after a node was executed, execution continues with the node connected to the leftmost edge starting under node. After that node and all its children have been executed, execution returns to the node connected by the next edge.
Some nodes require the conecpt of subsequence. In plab, it does not refer to all nodes executed after a node, but to the nodes connected by a series of outgoing nodes. Outgoing edges are displayed below a node, incoming nodes are displayed above it.Previous Chapter: Introduction