Show HN: What if the speed of light was 5 km/h?

The interactive demo sets the speed of light to 5 km/h, letting users accelerate with WASD and observe relativistic phenomena such as length contraction, time dilation, Terrell rotation, and Doppler shifts—including blueshift ahead, redshift behind, and transverse effects. As velocity approaches the 5 km/h limit, these effects become increasingly pronounced, mirroring real-world special relativity.