brainfuck in liquid
It can be shown that Shopify's templating language (Liquid) is Turing-complete. An easy way to prove this is to implement an interpreter for another Turing-complete language, such as brainfuck. Try posting a comment with the email "brainfuck" and some code as the body. It will run on Shopify's servers and output the value directly into the HTML. For example, ++++++++++[>+++++++>++++++++++>+++>+<<<<-]>++.>+.+++++++..+++.>++.<<+++++++++++++++.>.+++.------.--------.>+.>. is a good place to start. This one will take several seconds to run:...