I am reading some in Mark's book (white).

It's talking about the Method Finder.
I playing with it using the example.

The example is:

'abc' . 2 . $b

I accept and get similar results to the book.

To my understanding of the above I am providing an example of a
  'string' receiver . integer argument . character answer

So I play with it changing the string, the integer and the character.

Depending on how I change the string, integer, character changes the 
results.

Changing the 'abc' to 'zzz' gets an error.
   While 'bbb' 'bb' 'b' works and 'aaa' 'aa' 'a' fails.
Changing the 2 to 3 (or most anything else) gets an error.
Changing the $b to c (or most anything else) gets an error.

All of the above changes were done in isolation leaving other parts as 
they were in the example.

Error message:  No single method does that function.

Am I misunderstanding something about the Method Finder?
In my examples above I did not change the types of the information 
merely small changes to content.

Any help in understanding this is greatly appreciated.

Jimmie Houchin