The finalists of the Urban Prototyping: San Francisco competition are all easily replicable ideas that could spread to cities worldwide, from the whimsical (giant playable keyboard) to the serious (measuring traffic).

Open public space in cities doesn’t have to sit unused; just take a look at San Francisco’s Pavement to Parks project, which turns wasted space in streets into “parklets” where people can sit and relax. A group of San Francisco organizations have teamed up to enliven public spaces with Urban Prototyping: San Francisco–a project that aims to spawn a number of small-scale, replicable projects for public areas that can improve cities in some way.

The project, which is being put on by organizations including the Gray Area Foundation for the Arts (GAFFTA), the SF Mayor’s Office of Civic Innovation, and 5M Placeworks, recently held an open call for projects. Out of the 90 entries received, GAFFTA narrowed them down to 18 finalists–you can see our favorites in the slide show above. Those finalists, along with projects culled from a “makeathon” in the fall, will take over two blocks in downtown San Francisco for a street exposition in October.

All the finalists will receive a stipend, ranging from $300 to $1,000, to improve their projects. “Some are preexisting projects that would add another layer. There are a lot that have already made progress, done research,” says Jake Levitas, research director at GAFFTA.

Some of the projects, like the Clip and Slide, which turns any set of stairs into a xylophone, are whimsical. Others, like the DIY traffic counter for citizens, are more serious. But all of them are realistic enough that they can be showcased on city streets–if they’re lucky, for the long haul. “The great part about working with the city is that we can have open conversations with them about what’s realistic and what’s not,” says Levitas.

Check out the slideshow at http://www.fastcoexist.com/1680463/10-urban-projects-that-could-change-city-landscapes-for-the-better#1