Every world is an equation.
Change the equation.
Change the world.
The landscape under the ship is the graph of an EML tree, sampled every frame by the same evaluator that computes the force. Fly over a peak and the field is strong and you sink; fly over a dip and you rise. Nobody tells you the equation controls the world — it is the only thing that does.
Each world is a rung of the depth hierarchy, and what you may build in it is bounded by the depth you have reached. Climbing buys expressions, not speed. exp x costs one level. x + 1 costs four, and that is a theorem, not a curve someone tuned.
Open Build a World, rearrange the tree, and fly what you made. Every run has a code that reopens the exact world — same expression, same seed, same gates. The Compiler X-Ray shows that expression as EML, JavaScript, C, GLSL and Lean.
Two of the worlds are certified constructions
The game reads these statuses from the research record at build time. A rung whose evidence is missing renders as pending inside the game too — see the ladder.
The mathematics is readable without playing anything: the compiled modules are in /play/eml/, and the engine that flies them is in /play/engine/.
More experiments