OLPCities/Links
A "link" has 2 files. It's neither like 3D objects nor like Hard objects. The avatar can not go behind it. He can only "contact" the "shadow" (figure having the sufix "S") that will transport him to another place that can be another Lot, another City or a "normal" web-page.
The basic "link" is that to go to a "normal" web-page:
The "gates" are links to another Lot or City. There are a "gate-in" and a "gate-out". When the avatar arrives to a Lot he arrives going out of a "gate-out". If he goes to any other Lot he "contact" the "gateS" (a "shadow"):
