The basic function of the machine is straightfoward

• First rune is the same for everyone
• Second rune is one of three runes. This pool of three is the same for every player
• Third is completely random

My interest is not how the game decides which runes are actually perfect/green matches for that day, but if there's a constant pattern to what constitutes a close/yellow match.

 

My theory is that runes are placed into several groupings. If you ever pick a rune that is the same category as the perfect rune, you'll get a close/yellow match and red otherwise. As for the second rune slot, I suspect you should only get a close match for your specific rune out of the three possible ones.

 

For example, if the built-in groupings are

• Fire/Air/Earth/Water
• Mind/Chaos/Death/Blood
• Cosmic/Astral/Body/Soul

And the correct runes of the day for a specific player are Air/Chaos/Soul, then Fire/Mind/Cosmic would be Yellow/Yellow/Yellow and Mind/Earth/Water would be Red/Red/Red.

 

If these groupings remain static (though it's entirely possible that Jagex re-randomizes the groupings each day), then we could have a system for reducing the amount of trial an error as we'd only need to experiment with runes in the same category. You would narrow down the third rune by trying one rune from each group until you got a yellow and then zero in on runes within that group.

Today one of my perfect runes was Air yet I got blood as a close match, I thought the groupings might be rows/columns but this clearly shows otherwise. I'm not sure if they have a specific grouping that would make sense (i.e all elementals, all combat runes, support runes etc) in this case. Hope that helps a bit :D

I replaced muds with earths on the third slot. Went from 100 to 93 wax.

Slot 1: Perfect Death

Slot 2: Close Mind/Body/Soul, Perfect Water

Slot 3: Close Fire, Perfect Dust

250% more vis wax for daily challenge now, u serious Jagex?