http://www.lepp.cornell.edu/~seb/celest ... pet_v1.zip (150KB)

This image shows the carpet at the entrance to a model of the Hampton Court Maze, which is included.
One clicks on a 3D button to make the carpet move.
Note:
This Addon is incompatible with the Hale Telescope Addon.
If one is installed, you must deinstall the other.
Science and fantasy don't work in the same world

Actually, this seems to be due to a limitation in the implementation of Lua in Celestia, which may be fixed or worked around in a future version.