It's nice to see that has a brainfuck interpreter. I wrote a lisp compiler recently, then used that to write a lisp interpreter, and in both cases have a version of brainfuck in it.

That said interpreting the brainfuck mandelbrot program takes several hours. On an old CP/M system I have a brainfuck compiler that converts a program to Z80 machine code, and that same mandelbrot example runs in less than two seconds.

So speed isn't great, but having brainfuck really proves a toy system is "real".