Remember Hippo Rollers? A quick refresher, from our archives: "In rural Africa, women spend 26 percent of their time fetching water, often walking for miles with heavy buckets balanced on their heads. That's time that could be spent going to school, working outside the home, or teaching their children. The Hippo Water Roller eases the burden by allowing women to transport five times as much water with much less physical effort." The developers initially wanted to create a cheaper wheelbarrow, but realized that the wheel itself was the most expensive part. Their solution: put the water inside the wheel.The idea was that this cheap innovation would dramatically improve the quality of life of anyone whose daily routine required the schlepping of water. More than 30,000 rollers were manufactured and put into use, thanks largely to the work of NGOs and generous donors. But a new problem emerged: the design actually made it too costly to distrubute widely.That's why the folks at Hippo Rollers (Project H and Engineers Without Borders) went back to the drawing board to create a new design on the same principles, one that would be easier to transport. Their solution is pictured above and, through virtue of its stackability (the pieces "nest"), is much easier to ship: two and a half times as many Hippo Rollers fit in a shipping container now, as compared to version 1.0. They're looking to recoup some of the cost of creating a new mold, so consider donating on their website.Via Core77.