James Kanze wrote:

>> Start with the book /Design Patterns/, generally to learn what
>> the "point" of all this OO stuff is. You will notice most
>> patterns use only 2 layers of inheritance...
>
> The key above is "most patterns".

I wrote that because I didn't have /DP/ to hand. I suspect that no pattern
in /DP/ has more than two layers, and I suspect this answers the OP. 2.

--
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http://www.oreilly.com/catalog/9780596510657/
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