It took me a while to grok the y-combinator, but I eventually realized it's just a generic factory, as a trampoline, that ceases to return a function invocation

It took me a while to grok the y-combinator, but I eventually realized it's just a generic factory, as a trampoline, that ceases to return a function invocation, just the last value, when it reaches the fixed point -- so it can actually reach a stopping point and not cause infinite recursion, without needing a self-reference.