That problem is the complexity of redesigning software.
	When thinking about design, programmers prefer diagrams that abstract from the details in source code.
	However, current tools provide diagrams like the one on the left that quickly become as complicated as the program they’re trying to depict.
	The programmer can try to filter out what she doesn’t want to see, but usually it’s easier for her pick up a pen and paper and redesign by drawing only the parts she wants to see (like the diagram on the right).
	Unfortunately, the computer can’t help the programmer when she redesigns with pen and paper – and I believe that it should.