display Sierpinski triangle
(c) 2016 Daniel B Cristofani
http://brainfuck DOT org/

++++++++[>+>++++<<-]>++>>+<[-[>>+<<-]+>>]>+[
    -<<<[
        ->[+[-]+>++>>>-<<]<[<]>>++++++[<<+++++>>-]+<<++.[-]<<
    ]>.>+[>>]>+
]

Shows an ASCII representation of the Sierpinski triangle
(iteration 5)