I've had a few emails requesting this scheme so here it is for you all to view :-)
Here's a demo video here:
And a short description from the Zvex Website:
"I designed this new distortion generator, Machine, with some different limitations. Like try playing chords through it. Hmmm. But put it in front of any string of fuzz pedals, and try to make it disappear. Machine is actually a dual frequency-tripler circuit that uses crossover distortion for the first time in any pedal, ever. It generates the distortion of the wave in the sloped part of the cycle, instead of the peaks and valleys like all other distorters and fuzzes. In other words, it distorts when your guitar string is in the middle of vibrating, while it's swinging, not as it's turning around. That's the same place where your speaker cone is sort of coasting, between all the way in and all the way out. Where nothing is happening, this pedal happens. With Machine you can leave your favorite distorting pedals on and still add a new element of energetic grind."
It's using frequency triplers like Tim Escobedo's "Tripple Fuzz", they sound pretty cool (The Lovepedal Karl also uses this circuit structure):