GPT-5.6, Grok 4.5, Claude, and Muse Spark build the same 4 apps

GPT-5.6's new Sol, Terra, and Luna tiers go head-to-head with Grok 4.5, Claude, Meta's Muse Spark, and the open-weights crew on a raycaster, a Rubik's cube, a calculator, and Game of Life. Here's every build, with cost and latency.