EcoJar

Ecosystem simulator · iOS & Android

A sealed jar with no lid to open.

Sand, water, algae, a few daphnia. Then you leave it alone and find out whether it holds. If the oxygen falls, it fell because something in your jar breathed it.

App Store Google Play Both in review. Coming soon.
EcoJarA world that runs itself
A pixel-art glass jar at dusk, with sand, water, algae and drifting daphnia, above a panel of drawing tools.

What is actually simulated

An aquarium made of cellular automata.

Every grain of sand falls, every bubble rises, every alga photosynthesises, one cell at a time. Nothing here is decoration and nothing runs on a timer.

Oxygen and carbon dioxide

Real quantities, produced and consumed cell by cell. Nothing is on a timer.

Photosynthesis that follows the light

Algae stop making oxygen at night. You can watch the curve turn.

Animals that can suffocate

Fish die when the water cannot keep up with them. Usually that is your fault.

Twelve materials that behave

Sand falls and piles into slopes. Water finds its level. Glass holds. Nothing is scenery.

The jar, on a phone

No score. No daily reward. No timer to come back for.

Build a jar, watch the oxygen curve, and decide for yourself whether it is a good one.

EcoJarA world that runs itself
Twelve materials. Draw, then stop touching it.
Twelve materials. Draw, then stop touching it.
EcoJarA world that runs itself
The oxygen curve is the whole game.
The oxygen curve is the whole game.
EcoJarA world that runs itself
At night the algae stop, and it shows.
At night the algae stop, and it shows.
EcoJarA world that runs itself
Every species has a page.
Every species has a page.
EcoJarA world that runs itself
Who eats whom, and who pays for it.
Who eats whom, and who pays for it.
EcoJarA world that runs itself
Keep the jars that worked.
Keep the jars that worked.

What is not simulated

There is no water temperature.

Because this simulation does not model temperature. We would rather say so than print a number that means nothing. The same goes for anything else you do not see here: if it is not on the screen, we are not pretending to compute it.

Privacy

EcoJar collects nothing.

Not "anonymised". Not "aggregated". Nothing — because the app makes no network request of any kind.

  • No account. There is nothing to sign in to.
  • No analytics, no crash reporting. No such SDK is bundled.
  • No advertising, no advertising identifier (IDFA / GAID), no tracking.
  • Your jars stay on your device, in this app's own storage. Deleting the app deletes them.

Read the full privacy policy →