They're key components of BDUF — "Figure 7. Step 3: Attempt to do the job twice - the first result provides an early simulation of the final product." http://

They're key components of BDUF — "Figure 7. Step 3: Attempt to do the job twice - the first result provides an early simulation of the final product." http://www-scf.usc.edu/~csci201/lectures/Lecture11/royce1970.pdf http://www-scf.usc.edu/~csci201/lectures/Lecture11/royce1970...