A 3D-printed autonomous car, and more in the week that was

In other news, a water-resistant iPhone could lead to less gadget waste.

3D printing and autonomous cars are two of today's hottest emerging technologies -- so why not combine the two? That's the idea behind Local Motors' latest vehicle, which features a 3D-printed body, a windshield video screen and no steering wheel. Meanwhile, OX launched the world's first all-terrain flat-pack truck, which can be quickly shipped anywhere in the world. Cannae Corporation announced plans to test an "impossible" zero-exhaust microwave thruster that could revolutionize space travel. And Electra Meccanica launched SOLO, an affordable three-wheeled electric vehicle for one.

In energy news, this week Sonos Motors announced plans to debut a solar-powered car within two years, and Soel Yachts unveiled a sun-powered motorboat that glides through the water without making a sound. A team of Swiss researchers developed the world's most efficient solar cell, which can double the efficiency of rooftop arrays. And in Israel, researchers developed a new strain of algae that produces five times more hydrogen fuel during photosynthesis.

3D printers can create incredibly complex objects, but they don't lend well to on-the-fly improvisation. Meet the 3Doodler, an amazing printing pen that can draw wood, copper and bronze structures in mid-air. In other design and technology news, Egloo launched a brilliant electricity-free heater that can warm your home for pennies a day. We were glad to see Apple launch a new water-resistant iPhone, which should cut down on e-waste due to drowned gadgets. And a plant-covered mobile living room took to the streets of Europe to purify the air.