This is nice for visualizing an NFA and the minimized DFA for asome regular expression (note: regular!!): http://osteele.com/tools/reanimator/ http://osteele.co

This is nice for visualizing an NFA and the minimized DFA for asome regular expression (note: regular!!): http://osteele.com/tools/reanimator/ http://osteele.com/tools/reanimator/. The aforementioned tool also lets you give input and highlights the current states of each FA.