01 · Growth
The frontier fills
Each colony keeps a list of empty cells touching its edge. Every tick it grabs a handful at random and claims them. Randomness at the edge is exactly what makes the border ragged and alive.
The rules of the plate
Nothing here is drawn. It is grown.
Every colony is a real Eden growth cluster — cells recruited one frontier site at a time. No sprite, no loop of pre-baked shapes. What you see is the arithmetic settling.
02 · Contest
They meet, and hold
A cell can only be claimed once. Where magenta and teal collide, neither can pass — a seam forms exactly where their speeds balanced. Reseed the plate and the seam lands somewhere new every time.
03 · Inhibition
The disc clears a halo
Drop a disc and the drug diffuses outward. Inside its radius the agar goes clear and stays sterile — bacteria already there die back, and the advancing lawn halts at the ring. This is the Kirby–Bauer test, in miniature.
Read the plate
Four things, one glance.
Agar medium
amber · unclaimed nutrient
Colony M
magenta · seeded left
Colony T
teal · seeded right
Clear zone
pale · no growth
A wider zone means a weaker bug — or a stronger drug.
Ciprofloxacin punches a broad, sharp ring; erythromycin barely clears its own edge when the colony shrugs it off. The tray is ordered the way a lab reads results: measure the halo, and you have your answer in millimetres.