I believe the important thing is that the goal is just a placeholder for whatever you believe is progress, generally. So it's incredibly fluid if you allow it to be.

For example, I have been working on a pinball simulation, and my attitude is very Forever Project in most respects. I first did almost nothing in terms of productivity, and just played pinball games and became familiar. Occasionally I poked around at how the real games were made and compared them with simulations, and developed some distinction between "pinball video games" (which made up their physics freely and attached video game gimmicks) and "pinball simulations" (which largely stuck to realism as a benchmark). I took a class where I wrote a story about someone transformed into the ball by a "pinball vampire". This character had already been knocking around in my head, but now the concept was solidified into something which suggested an original game. I played in a pinball tournament, and got a sense of the spectrum of skills and personalities and how far I could take my own playing skills. I debated options for what I would do to further my study of the game, finally settling on simulation gameplay. The specifics of the game as a product could remain open: the goal now, which I've spent some months on, is simply to reproduce a well known game, "El Dorado", as well as I could manage. This has turned into time working on each mechanism and making iterative designs for improved accuracy. The other day I got in an order for real parts so that I could take better measurements.

Once the prototype is done - and done is a thing I can claim whenever, but I gave myself a time limit around the end of this month, early next month - I plan to put it aside for a bit, because I have other things I want to focus on, but I also intend to come back and start developing it further.

So while I have had goals along the way, none of them are do-or-die. Rather, it comes from a place of abundance. There's always going to be more to study, so pick a few things, and see how far I get.

I already know that the physics in my sim are not where they could be, despite my efforts: just the other day, I was linked to a paper on a new position-based dynamics solver which has groundbreaking capabilities for deformation and restitution(important things to model in a game with fast rubber deformations). On the one hand, I want it, but I also know it's getting me off topic, because I'm not engaging in this project at the level of using the newest technology and techniques, but rather, engineering a design using the things that are commoditized, well-tested. I am using the stuff built-in with Godot Engine, and seeing what I can get out of it. The goal is there to give me a benchmark, not to be my finish line.

And as article states, it's not the most natural thing to run a Forever Project if you've just come out of school and everything's been about getting the grade. The overarching goal is something more like "I want to let myself struggle and think deeply about this for a while." Because if my goal were "make a pinball video game" alone, I could easily have had something up and running in two weeks. It would be disproportionate, have completely wrong behaviors, no understanding of layout or game flow, and generally be trivializing of the topic. That I have a prototype that is carefully measured, emulates something specific and is built on numerous experiments instead reflects a desire to go deeper.