Variables: 
int[1]: "f.x" 
int[2]: "f.y" 
int[3]: "f.z" 
int[4]: "f.w" 

Event graph: 
event[0]: fork: null, #pred: 0, succ: 1 

# process[1]:
event[1]: fork: , pid: 1, #pred: 1, succ: 3 4 
event[2]: join: , pid: 1, #pred: 2, succ: 1 
event[3]: assign: f.x := f.y, pid: 1, #pred: 1, succ: 2 
event[4]: assign: f.z := f.w, pid: 1, #pred: 1, succ: 2 

