The National Museum of Mathematics opened to the public Saturday in Manhattan.
The museum is aimed at kids aged 8 to 13, and curators have given the place a playground feel.
The 40 exhibits include a "wall of fire" made up of laser lights that teaches kids about geometry and a square-wheeled tricycle that still manages to produce a smooth ride thanks to a wavy track.
Founder Glen Whitney says the idea is to show people the "fun, beautiful" things done with mathematics.
The museum occupies the first two floors of an office tower across from Madison Square Park at 11 E. 26th St.
Tickets are $15 for adults and $9 for children. The museum is open daily 10 a.m. to 5 p.m.