A cycle-mad friend in New Zealand sent me the pics below of a three-wheel-drive recumbent tadpole rear-suspension trike that is in the pre-production stage in Russia. Ordinarily, I would not mention commercial builds, but this one has a couple of features that might be of interest to future Zombie creations. The builder's name is Alexei Soloviov, and he calls his creation the S4 3x3. The two front wheels are driven via drive shafts and universal joints, and the rear by chain & sprocket. He didn't mention anything about a differential mechanism, and it isn't obvious in the photos. I believe he has or is in the process of putting together a web site.

Apparently there is a group of home-builders in Moscow called "Club Rastabike Moscow, and they have built several other unusual bikes, trikes and velomobiles.

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ID:	4282 The "S4" three wheel drive trike with rear-wheel suspension.

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ID:	4284 Detail of the mid-drive Derailleur. At first glance it looks like a single chain on top, but there are actually two identical sprockets on the inside, with one chain leading to the rear wheel and the other connecting the pedals to the Derailleur and front wheel drive axles.

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ID:	4283 Detail of the front wheel drive Universal joint. I believe the braking is via drum brakes.