I think @pico8bot on Twitter is pretty cool. Just for fun, I've reimplemented the image generation algorithm in PHP.

I looked at the original source code to find out how the % operator works, the colour palette, the number of frames, how x and y are set, and the width and height: https://github.com/Objelisks/picobot/blob/master/bot.js

• Full language support:
  • Operators: +, -, *, /, %
  • Functions: sin, cos, abs, tan2, sqrt, floor, max, min
  • Variables: x, y, t
• Uses PHP's tokeniser because I'm lazy
• Shunting-yard parser which generates abstract syntax tree
• Two evaluation methods:
  • Naïve recursive evaluator
  • JIT compilation to PHP code

PHP >= 7.0

PHP Gd extension

$ php pico8bot.php <expresssion> <outfile name>

Currently doesn't do animation or give a choice of evaluator (it always uses JIT).

e.g.

$ php picto8bot.php 'sin(2.07*x)*cos(9.76%8.24)*flr(max(y, 2.51))' test.gif