1  =>((a|b|\p{Nd}){1,2}|aaa|bbbb){1,2}
 2  bab
 3  aaca
 4  aaabbbb
 5  a0b
 6  aa0aaa
 7  b0aaa
 8  =>(\d{1,3}\.){3}\d{1,3}
 9  1.2.3.4
10  1.22.333.44
11  1.2.3
12  1..2.3