Inserting points (pixels) between elements of NSString in a UILabel -

I am preparing a ULLL, its text is an NSString that is made up of 3 different variables such as:

  NSString * myString = [NSString stringWithFormat: @ "% @% @% @", string1, string2, string3];  

What is the best way to separate the string 1, string 2 and string 3 of the number 1 and not the character space?