1Regexp: ((a|b|\p{Nd}){1,2}|aaa|bbbb){1,2}
2bab: Ok
3aaca: Fail
4aaabbbb: Ok
5a0b: Ok
6aa0aaa: Fail
7b0aaa: Ok
8Regexp: (\d{1,3}\.){3}\d{1,3}
91.2.3.4: Ok
101.22.333.44: Ok
111.2.3: Fail
121..2.3: Fail
13