I know it sounds silly, and I know the answer is most likely "not possible". But I am just curious. Could theoretically the Mac Pro 1,1 run macOS Mojave? It is already supposedly possible to run El Capitan on it, by modifying the installer to work with it. And other mac's are capable of running it because of the Mojave Patcher from DosDude1. So what if with those powers combined, could it theoretically run? And if possible, could one install a METAL graphics card into the mac to make it slightly more compatible?