Marko Schulz <in6x059 / public.uni-hamburg.de> writes:

> Changing your
>    /^(11+)\1+$/
> into 
>    /^(1{2,})\1+$/
> still lets the program run correctly.
>
> But when I tried the following
>    /^(1{2,}){2,}$/
> it didn't anymore. 

looks like you made two mistakes in that last transformation:

 1. you dropped the \1
 2. x+ is equivalent to x{1,} not x{2,}

so you should have ended up with:

 /^(1{2,})\1{1,}$/

m.