You can easily create interface vtables in C. These vtable (ptrs) don't have to be put into the objects themselves, which is a historic mistake that got thrown

You can easily create interface vtables in C. These vtable (ptrs) don't have to be put into the objects themselves, which is a historic mistake that got thrown into C++ and other OO languages. The vtables can be passed as arguments to any operation, making them closer in power to type-classes than OO interfaces (i.e: much more powerful).