Build a production line suspended in empty white space, no floor, no horizon, and a camera that can fly underneath it. Droppers feed material onto belts, upgraders raise its value, and a green sell plate turns it into money.

The whole game is one constraint: only so many items can exist on the belts at once. A dropper adds one, the sell plate removes one, and when you hit the ceiling the droppers visibly stall. That turns every metre of belt into a real cost and makes the question "what is one slot worth?" the thing you actually play.

There are two families of upgrader and the shapes tell you which is which: tall thin posts multiply, low wide ones add. Adders are flat, so they pay off on cheap material; multipliers scale, so they pay off on expensive material. Adding first and multiplying second measures 2.42x better than the reverse.