The "Starter Worlds" are the best Worlds to use to write your own Worlds. They are designed to show you how to code different types of Worlds. These are plain text. You can view the source code.
The easiest parts of the code to change are in the "tweaker's box" at the top. You should be able to change things in this box without being a programmer. Go and try it:
The following Starter Worlds use the Three 1.0 API. This has Three.js graphics support and built-in mouse (and touch) camera control. This API is Three.js release 80. Some of these Worlds use a Mind. Some do not. Click World image to run the World.
The following Starter Worlds use the Physics 1.0 API. This uses Three.js with mouse (and touch) camera support and built-in physics support from the Physijs library. Click World image to run the World.
The following Starter Worlds use the Canvas 1.0 API. This does not use Three.js or any graphical library. It just has a canvas, on which World authors do their own 2D or WebGL rendering. This can make for a more complex World, but is needed for some authors. (Three.js or other libraries would only get in their way.) Click World image to run the World.
The following Starter Worlds use the P5 1.0 API. This uses the P5 graphics library. Anything written in P5 should run on this site using this API, with some small adjustments, explained on the API page. Click World image to run the World.