/
^ # start of line
(?=(?:.*[A-Z]){2,}) # 2 upper case letters
(?=(?:.*[a-z]){2,}) # 2 lower case letters
(?=(?:.*\d){2,}) # 2 digits
(?=(?:.*[!@#$%^&*()\-_=+{};:,<.>]){2,}) # 2 special characters
(?!.*(.)\1{2}) # negative lookahead, dont allow more than 2 repeating characters
([A-Za-z0-9!@#$%^&*()\-_=+{};:,<.>]{12,20}) # length 12-20, only above char classes (disallow spaces)
$ # end of line
/
gmx