Each year Swiss tuner and auto maker Rinspeed comes up with a crazy concept car for the Geneva Motor Show. This year’s concept is based on a smart fortwo.

What Rinspeed has done is simple but kinda clever. They realized that the smart has no boot so they came up with a docking system called “backpacks on wheels.” It’s like a big cubbyhole with wheels, a sort of single-axle solution. You attach it to the back of your fortwo and there you go!

It looks a bit silly to be honest, but it adds a fair bit of practicality to the tiny city car. Rinspeed sets an example: Imagine you are a pizza delivery guy. The Dock+Go will be perfect for you as you can fit it with a heated box.

Now, Rinspeed knows they can’t just present a box on wheels at the Geneva show. So they thought of an ingenious feature to make it more interesting. The dock can be used as a range-extender for any electric car. Here’s how it works:

An “energy pack” with a combustion engine or range extender, packed with batteries or powered by a fuel cell, provides the decisive added range for reaching more distant destinations. The equally simple and clever trick: the docked third axle drives the rotating second axle and thus recharges the on-board battery of the city car. And thus the first Vario-Hybrid, as Frank M. Rinderknecht refers to his range donor, is born. In the garage at home the batteries of the energy pack are recharged with solar power from the roof, making living and driving without any CO2 emissions a reality.

Very clever. But there’s no getting way from the fact that a six-wheeled smart looks plainly ridiculous.