= {a,b,c} L(r)= {all strings with at least two consecutive aa} r=? - = (a+b+c)*aa(a+b+c)* L(r)={all strings with no more than two a's} = (b + c)*(1 + a)(b + c)*(1 + a)(b + c)* L(r) = {All strings in which all runs of a's have lengths that multiples of three} = (aaa + b + c)* r= L(T) = {all strings containing no more than three a's}