Falling sand demo https://git.rtk0c.com/sand-physics/atom/src/rand?h=master 2025-05-18T01:03:44Z 2025-05-18T01:03:44Z rtk0c mail.tianyig@gmail.com 2025-05-18T01:03:44Z urn:sha1:e041b2a3ea3835a6b3a59dfbd1f24a86fd104396 - dirty rectangle (and the math library thereof) - drawing it - no more std::vector in Sandbox - single step - cycle counter display