7. Кубик Рубик и теория групп
<a href="https://en.wikipedia.org/wiki/ru:%D0%A1%D0%B0%D0%B2%D0%B2%D0%B0%D1%82%D0%B5%D0%B5%D0%B2,_%D0%90%D0%BB%D0%B5%D0%BA%D1%81%D0%B5%D0%B9_%D0%92%D0%BB%D0%B0%D0%B4%D0%B8%D0%BC%D0%B8%D1%80%D0%BE%D0%B2%D0%B8%D1%87" class="extiw" title="w:ru:Савватеев, Алексей Владимирович">w:ru:Савватеев, Алексей Владимирович</a>
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