How to run Worlds

Worlds that can be run are usually indicated by a world image to click on, like these:

Blank Three.js World
521 runs ♦ 2 likes
Starter user
A simple starter World. An Array of spheres. Painted with textures. Random motion.
Simple World
845 runs ♦ 2 likes
Starter user
Simple World with a Mind-controlled agent, randomly-moving enemy, paint blocks with texture.

Sometimes the run is done by clicking a run button, like: and:

Try all of the above. They are working links.

A run opens a new tab or window

  • The run takes place on the client side in your browser.
  • A run opens a new tab or new window.

  • Camera control: Depending on the API, it may be possible for the user to control the camera in the run window. Try mouse drag (or touch drag on a touch screen) to move the camera. Try mouse scroll (or touch pinch on a touch screen) to zoom in and out.

To close the run window

To close the run window:
  • Click on the Close icon:
  • Or click on the normal tab or window close icon.
  • Or use a keyboard shortcut like Ctrl-W.
  • See keyboard shortcuts for closing tabs and windows on different operating systems.

Warning to all users: A run is like a random website

All users should be advised that a run window is essentially a third party website.

Our philosophy is to allow the upload of almost any JavaScript, subject to some basic checks. We do not want to put limits on the imagination of authors. Authors can write to the run window, redesign it and insert links into it. Essentially, World authors and Mind authors "own" the run window, as if it was their website.

So you should treat each run as if it is a new, unknown website that you have landed on after following a link on social media. Do not enter any passwords (even Ancient Brain passwords) into a run window. Do not type any sensitive data into a run window. Follow any links in it with caution. Watch out for it redirecting to another server. Read any user comments. Check out who wrote it.

Please report misleading or malicious Worlds and Minds to and we will delete them.

Note that:

  • Login pages are on the server:
    These pages are safe.

  • Run windows are on the server:
    These pages are untrusted, and may even redirect to a new server entirely.

Run "logged in"

There is an option on each World page to do a run "logged in". This is a special type of run to allow users save their place in a game, or save something they created in a World.

The run window is not really logged in as you, otherwise someone else's JavaScript, which is running in the run window, could damage your account. Rather, the run window is given a special "ticket" which gives it permission to save data connected to this World in this single file in your uploads directory:


The run window can later read back from that file. (In fact, any run can read that file. Like all your uploads, it is public.)

Here is an example of a World with "save data" and "restore data" buttons when you run "logged in":

343 runs ♦ 2 likes
Starter user
Use keyboard to draw blocks like in MineCraft. Use arrow keys and PgUp, PgDn to draw. Can save w...

The background is a program, showing the JavaScript graphics used on this site.

© Ancient Brain Ltd. All rights reserved.

Ancient Brain ™ is a trademark of Ancient Brain Ltd.

Beta      Bug bounty      Contact      Stats      The name      Terms and conditions