[squares2.b -- compute square numbers
(c) 2016 Daniel B. Cristofani
http://brainfuck.org/]

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

This program outputs square numbers. It doesn't terminate.