A $350 toilet powered by worms may be the ingenious future of sanitation that Bill Gates has been dreaming about

Tiger Toilets run on poop-eating worms and cost less than traditional sewage systems. All they leave behind is water, CO2, and a little fertilizer.

These 22 sketches make complicated financial concepts simple enough to fit on a napkin

Napkin Finance aims to break down complicated financial concepts through text, video, and illustrations. It covers topics like insurance, stocks, debt, student loans, crowdfunding, estate planning, and even bitcoin. Here are some of its best illustrations.

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