Here. It was more a test to see how easy it would be. My head broke several times while I was building it, even though I had it printed off in front of me. I just kept losing my sense of direction.
Also, I've learnt to build it flat on the ground, instead of falling off lots while it's in the air.
That would have been easy, as would have trapdoors been.
My plan is to have an extended piston holding back lava, when you press the wrong button, it retracts. The hard part was getting it to retract for long enough to allow lava through.
The insanely difficult next bit is to have it on multiple levels, where the right answer releases water instead of lava, and you can swim up through the water to reach the next level. I don't think that's feasible though unfortunately, it's going to be hard enough for one level!
Having said all that, some preople really do have too much time on their hands, but make awesome redstone stuff - see this piston-engined train for example:
http://www.youtube.com/watch?v=IzzxS_MP8sQ
Well, the first 'draft' of it is at the top of my tower
Images:
It's sort of finished now - as it's at the top of the tower, I don't have that much room.
Give it a try, just have some water handy!
I can't remember if I left the lights on or not though, so you'll have to hunt around for the switches if you can't find your way to the top...
Also, anyone know of a decent guide to making Rail junctions?
So I don't need to ask Kev every time!