how do I put in a sky with clouds, is that an object I can add? Where is it. Must that sky be cobalt blue?

Paul,

To have an sky having clouds in movement you need to add, to the function
"initialize" of the Class CobaltWorld:

 tframe := TSkyBox new initializeWithFileName: 'JUL'.
 tframe step. " Make the sky spin. "
 space addChild: tframe.

Commentaries in Smalltakk are between quotation marks.

It works for Croquet-Cobalt and I imagine that it's working also for
Web-Cobalt, like you can test loading, at the "Cobalt browser":

http://www.dmu.com/cobalt/lesson4+sky.c3d

(It's the same 3D lesson 4 with the new sky)

Please, let me know if it's working OK because, like I do tests at a "not
clean" computer, sometimes I think that all is OK, but it's not. Because my
Cache has many thinks that a "clean machine" doesn't have.