Brainfμck is a very simple programming languages with only 8 possible instructions. In this interpreter, you can change the speed by setting a delay for each operation. The pointer is represented with <. Here's an example program : ++++++++++++[>++++++>++++++++>+++++++++>+++++++++>+++++++++>+++>+++++++>+++++++++>+++++++++>+++++++++>++++++++>+++>+++<<<<<<<<<<<<<-]>>+++++>>>+++>---->+++>+++>++++++>>++++>--->----<<<<<<<<<<<<<+[>.>.>.>.>.>.>.>.>.>.>.>.>.<<<<<<<<<<<<<]<.+++.------.--------.>>+.>++.
You should activate turbo mode turbo mode by clicking Shift+Flag, it runs a lot faster.