Ultrathin business card runs a fluid simulation

August 8, 2025 · Nicholas L. Johnson

URL: https://github.com/Nicholas-L-Johnson/flip-card

“A business card that runs a fluid-implicit-particle (FLIP) simulation.”

Someone built a business card with an embedded display that runs a real fluid physics simulation. It has a rechargeable battery and USB-C charging. The firmware is written in Rust for an RP2350. This is absurd and wonderful. The best engineering projects are the ones that exist purely because someone wanted to see if they could.