Let's play a game — and include an entire city.

That's the idea behind one Reddit post that proposed building a citywide scavenger hunt in San Francisco with hundreds of 3D printed toys.

The man behind the post is Ben Baltes, a 25-year-old software developer who is a co-founder of a 3D printing toy start-up in Oakland. In a phone call Monday with Mashable, Baltes said he's been thinking about the project for about two years and is framing it as "more of an experiment than a game."

He and a core group of game planners have settled on calling it "Hidden City" and are serious about making it a reality. Baltes posted the idea on Reddit last Tuesday and said if he got more than 150 "up-votes" he'd continue planning. In less than a week he's received more than 400 votes.

He and his team plan to strew 200 toys across the city — a monkey climbing a telephone pole, a mouse near a gutter, or a sloth on a railing, for instance. Each critter will have a unique link and/or QR code printed on it, which will lead the finder to a website about the figurine and its travels throughout the city.

Finders can post about their experience finding the toy or add a picture with the toy — participants are encouraged to get creative on how they'll contribute to the game. Then the game ideally continues because, within 12 hours of finding the toy, the finder hides it in a new location for someone else to discover. And on and on it goes.

An open Slack channel for the game is helping devoted game developers organize the game, which will hopefully debut by the end of February, Baltes said. A shared spreadsheet is also filled with tasks including app development, toy creation, game running, expenses and other details.

Baltes said printing 200 critters and monsters will be time consuming since it takes about four to five hours to print one toy. His 3D printing start-up is sponsoring the project, though, and providing plenty of access to printers.

The small Reddit community has joined forces with Baltes so he's not managing his side project on his own, but he wants the game to become a bigger community effort. He envisions it catching on and spreading to other cities, or being a total flop if people just take the toys or troll the website.

But mainly Baltes "thought it would be cool to print things to find" and track where they go. "This is my effort to make the world a little more interesting."