Engin wrote:wow, how come this huge strength improvements?
critter grows up in the last years rapidly, then i wondor how he doing this, i think it is impossible to doing such improvements in a short time, may he working very hard on critter or he is cheating and cloning from other sources.
OR he can MAGIC !?
i am doing this hobby, but have only reached about 2700 elo , in this way i am now a little demotivated from computerchess

As for the "How" of it, I think the following:
Almost all of the chess programmers are examining the code of strong engines like Fruit, Stockfish, and IvanHoe. If you are just reading the code for understanding the ideas, in my opinion there is totally nothing wrong with that. And if you use the ideas (I am not talking about cut and paste) there is nothing wrong with that either.
Literally every chess engine on earth is, in some sense, a clone. That is because nobody, not even Dr. Hyatt, has invented every idea in their chess engines. Sometimes these ideas are lifted from chess papers written by chess programmers. Sometimes these ideas are lifted from examination of someone else's code. Sometimes these ideas are lifted from reading responses in boards like this one. Sometimes these ideas are lifted in conversations with other chess programmers. Sometimes these ideas are lifted in collaboration with other chess programmers.
There is nothing wrong with that. Now, personal satisfaction can come from:
1. Understanding an algorithm and writing your own version.
2. Subsequent improvement of that algorithm with your own fresh ideas.
3. Invention of a totally novel way of doing things.
And many other ways.
If someone were to grab 50K lines of chess code, ram in a stick and stir it around, and then slap their name on it, where will the personal satisfaction come from that? I totally don't understand it.
If you were to take the low road and tweak some giant killer, probably a group of people would hail you as a hero. But you will still need to answer to your own heart at some point.
So I recommend the Spike Lee quotation: "Always do the right thing."
What I think is the right thing is not right for everyone. Some would be deeply offended at reading someone else's code, understanding it and writing my own version. If they put a patent on their algorithm, and publish that fact, I would not duplicate the idea (and I would also not like their choice, but would obey it). Right and wrong are clouded in this arena by the fierce competition. I understand this also. If you have labored for 5 years to write your own chess engine from the ground up and someone else steals someone else's code, change literally 5 lines, and then beat you in a big public contest then I think you have a right to be flaming mad.
Here is my bottom line:
No matter what you do, some people will hate you for it and some people will love you for it. Some will hail you as a hero and some will pan you as a demon. So be true to your own heart and I think you will find the path of chess programming happiness.
P.S.
It's not a path to riches.