“Pee planters,” fruit fences, and LED hopscotch might sound like a normal weekend in San Francisco, but the Urban Prototyping Festival isn’t exactly aiming for normal.

Click to embiggen.Urban Prototyping

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Part art-installation festival, part pop-up urban-planning think tank, this unique green fest convened for one day this weekend in S.F. to take on city problems with a heavy dose of whimsy.

From the San Francisco Chronicle:

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The festival began this summer in Singapore, and Saturday’s event was the first stop in the United States, taking up three blocks near Fifth and Mission streets. The idea is to create a “living laboratory” of inventions that transform public spaces and make them useful, educational, interactive or just plain fun.

One group of participants proposed a “10-mile garden” that would make use of curbside space in front of fire hydrants.

If every fire hydrant in San Francisco had a garden in front of it, all of that space added together would be 10 miles of extra greenery in the city, [said Mona El Khafif, an urban design professor at California College of the Arts].

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And if there happens to be an emergency requiring use of a hydrant with a garden in front of it? “The trucks can just run over the garden,” she said. “We’ll replant if we have to.”

Some of the other inventions included newfangled bus stops, a glowing crosswalk, and garden urinals that would “turn a nuisance into a nutrient” for attached bamboo biofilters.

The urinals are attached to planters, and the wastewater is filtered and used to water trees or flowers. The idea — which the designers call a “PPlanter” — is to take an urban problem like public urination and turn it into something beneficial.

If street urine were used to fertilize instead of left to fester, I can only speculate at all the foliage that might bloom in downtown San Francisco.