This is a pretty good video about the subject as well: <a href="https:&#x2F;&#x2F;www.youtube.com&#x2F;watch?v=_ezhdhHNku0" rel="nofollow">https:&#x2F;&#x2F;www.youtube.com&#x2F;watch?v=_ezhdhHNku0</a> - Coded Mask - Sixty Symbols