If your school has caught on and blocked the specific repository, you can look for alternatives that use similar "stealth" tactics:
If the site loads but games are stuck, try a hard refresh (Ctrl + F5) to clear the cache, or switch to a different browser tab and back to allow the emulator to catch up. gnmath github io unblocked updated
Unfortunately, raw GitHub.io subdomains sometimes get caught in broad filters. Additionally, many educational institutions block any site that allows "script execution" or "console commands," fearing that students might use them to bypass network restrictions. If your school has caught on and blocked