We use a simple program with no obvious natural interpretation to contrast the Byrd box model with the AND/OR execution tree. See figure 5.3 for the program and for a graphical representation of the program's structure using the Byrd box model. Figure 5.4 shows the same program's structure as an AND/OR tree.
Figure 5.3: Program Example with Byrd Box Representation
We consider how the goal a(X,Y) is solved.