The fly is a simulation of one real fruit fly's central nervous system: 165,122 neurons and 10,228,000 connections measured by electron microscope (FlyEM male CNS v1.0), run as spiking neurons after Shiu et al. 2024, continuously, never reset. How it was raised, what it learned and what went wrong on the way is in the FlyStream training report (pdf).
The tower has six floors, and each floor is one piece of a story: who, where, when, what is happening, a twist, and how it is painted. A floor is a three by three: a landing pad in the middle and eight doors around it. The doors are written for that floor by a language model from the pieces already taken, and every door carries what the fly can sense: a smell from the ten its receptor neurons are wired for, a temperature, a brightness. The fly lands on the pad with a minute on the clock. Its nose gets the doors' smells fading with distance, its eyes the brightness ahead, its body the tile under it. Its descending neurons are read as walking, steering, stopping, jumping. Every time its proboscis motor neuron fires on a door, that is a taste, and the tasted doors light up. At the buzzer the door it tasted most opens; if it tasted nothing, whatever it stands on opens: a door is the floor's piece, the pad is a skipped floor. The fall is real wind on its antennae until the next floor is written. At the bottom the pieces become a story and a prompt, painted by GPT Image 2.5 through OpenArt, and the fly flies back up.
What is real: the wiring, the spiking, which neurons fired, which tile it stood on, what its antennae got in the fall. What is ours: the tower, the sensory table of each door, the movement mapping, a weak steady drive to the walking neurons that stands in for the walking state a living fly has, and the receptor neuron sides, inferred from where their synapses land because the release gives them none. What is borrowed: the doors, the story, the title and the commentary, written by a language model, the last one from the receipts only. The fly has no ideas about stories. It has a nose, eyes, legs and a lot of patience.