Write a program in ValueScript

[voltrevo]

We need more programs showcasing what ValueScript can do.

If your program is relatively small, consider including it in inputs/passing and add the test_output header. Otherwise, add a link to it in README.md or wherever is most appropriate.

I appreciate that these programs are unfortunately quite limited at the time I write this. It basically has to be a computer sciency theoretical program like a sort algorithm. Interop with other systems is coming, and programs that use that interop will certainly be eligible for this good-first-issue too.