I can't get the rotating cube to run, (plugin problems like you say)

If you do see the image, only it is not rotating, maybe it is the matter of security setting of the browser. My Internet Explorer was not scripting when "Active scripting" was set to "Ask"; I had to set it to "Allow".

but downloaded source of the embedded svg and like the cloning relationships betweeen the unfolded cube and the '3d rendered' cube.

Can't imagine how you do the rotation with scripting - can SVG handle simple perspective rendering?

I compute the 3D transformation from the plane of a side to the plane of the view, and then set the 2D submatrix of this transformation matrix to the "transform" atribute of the clone.

In this way, the parallel projection (a view from very far point) can be done, not the central projection from a near point.

What's the plugin I need - my browser can't auto update plugins automatically because of enterprise firewall controls.

I am working on Windows 98 and Windows XP with Internet Explorer and Opera; and on Fedora Linux with Mozilla.

Adobe SVG Viewer downloaded from http://www.adobe.com/svg/viewer/install/

Are there rights reserved on this image?

It is public domain.

P.A.