itch.io

(1) is a very good point that I completely overlooked! When programming in FRACTRAN, it's usually the case that you know in advance the small list of primes that will be relevant to the problem, so you can always find a "13" for any given program.

(2) One might imagine an extension of FRACTRAN allowing fractions with the following behavior: If the number is divisible by 66, then multiply by 1155/66 = 35/2, and if it's not, move on to the next fraction. Normally if you entered 1155/66 it would cancel down to 35/2 and so the fraction would activate on any number divisible by 2, not just those divisible by 66.

This extended version of FRACTRAN is expressively equivalent to ordinary FRACTRAN, where fractions always get canceled. What's happening is that nocancel mode is translating your code into an equivalent valid program, using the same technique as in my solution to level 17.

I believe I have fixed the loop detector to correctly handle terms that evaluate to infinity. I've also added a "Max Iterations" input box so you can increase the number of iterations before the simulation gives up.

Thanks! Nearly everything is stored in terms of prime factorizations, except the loop detector uses their calculated values as javascript numbers. All of these large numbers 2^1234*11, 3^4321*13, 2^1134*31 evaluate to infinity, which we've seen before, so the loop detector thinks we're in a loop. And, yes, the maximum step limit is also too small. This should be an easy fix. The interactive is just an html file in an iframe, so you can just view its source directly. I didn't apply any compilation or obfuscation to the code.

This is great! It's got a clever premise, just the right level of flexibility that the puzzles are interesting without having too many solutions to test, and great animation and sound. I wonder how effective this (or something like it) could be for helping students learn function composition.

Clever! Consider having the marble change in size: it would really show off the tech.

Feels very abstract! I like it. 

Fun to play! Gets really fast around level 7

That was fun!

Amusing take on the premise!

Fun premise! Good old-school graphics.

Moving around in this game feels really great! Locking the cursor to the window or making it fullscreen could make it easier to move the car away from the edge.

Fantastic! Feels like trying to program autonomous robots.

Neat premise to try to wrap my brain around. Looks and sounds good. Consider having the move light in/out (scroll wheel) feature work in the menu.