Ryan Doyle of the Detroit-based team, Detroitus, works on an invention at the Recycle Here! garage during the Red Bull Creation on Thursday, July 10, 2014. Red Bull Creation is a 72-hour long competition, which brings seven teams with top artists, hackers and builders from across the country to create an invention that solves a mystery problem revealed to them in the beginning of the contest. This yearâs challenge is âReinventing the Wheel,â all pieces will be judged and winners announced Saturday, July 12 at Eastern Market. (Elaine Cromie | MLive Detroit)

DETROIT, MI - In the middle of the Recycle Here! workshop hangs a giant clock counting down the hours left during the Red Bull Creation challenge Thursday.

Seven teams from Michigan, Minnesota, Illinois, California and Arizona are competing in a 72-hour-long, live-build competition for a piece of the $10,000 cash prize.

Teams consist of artists, hackers, builders and inventors who were given the topic Tuesday night, hours before the competition started Wednesday morning at 8 a.m. Building will end Friday, July 11 at 8 p.m. The inventions will be judged and displayed at Eastern Market on Division Street on Saturday from noon to 6 p.m. This year’s subject is “Reinventing the Wheel.”

Teams use repurposed materials and recycled matter from around Detroit. During the live-build, team members were encouraged to explore Detroit and look for building supplies, said Tyler Hanson, social media manager for "New Creatures," a supporter of the event.

“We’re trying to use all local suppliers or American-manufactured goods,” said Joshua “Bacon” McAninch of team Detroitus.

The competition is bringing four veteran teams back MB Labs (Chicago), 1.21 Jigawatts (Minneapolis), i3Detroit (Ferndale) and Maker Twins (Phoenix).

Two rookie teams include Tactical Urbanists (San Diego) and OmniCorpDetroit (Detroit) and a third “house team,” Detroitus (Detroit), which operates the co-op space at Recycle Here! where the competition is being held, are also competing.

Teams could be seen working with wood, building structures, welding, and even using a 3-D printer. One team was building a ferris wheel powered by an app designed to serve vegetables to people. Another team was building a large-scale typewriter to print art work on walls.

Team members were secretive about their designs. One hinted they were building some sort of bench to be placed around Detroit, while others wouldn't give any indication of their creation.

See the photos in the gallery above for a look at the competition.