Brilliant gardener

I want to please the respected habrasoobschestvu another interesting task, it seemed to me an enlightened company worthy of attention and I offer it to you, friends.

You are a gardener. The customer - a very capricious person offered an impossible, at first glance, work:

take 10 trees and plant them so that you get 5 rows, and in each row there are 4 trees ...
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The problem is solved, I checked :)