Its beautiful to see the "check if number is a prime" regex as a diagram: ^1?$|^(11+?)\1+$ I noticed two glitches: 1) It gives me the same output image for these two different regexes: ^[a-x]*yo$ ^[a-x]+yo$ 2) It gives me a server error for this: a(b*(c*(d*)*)*) Edit: I was wrong about glitch 1. See below.
> ^[a-x]* yo$
> ^[a-x]+yo$
No, it does not.
When you do (something)* , pay attention to the additional path that is created that circumvents the (something) box. With (something)+, there is no such path.