I'm sure you know about it here is the complete(?) series...
Level 1: Crimson room
http://flash.qbol.net/pl;p/youxi/images/04042203.swf
(hint: code is1994)
Level 2: Viridian room
http://www.fasco-csc.com/works/viridian/viridian_opening_e.swf
Level 3: The Blue Chamber
http://www.killsometime.com/games/swfs/The-Blue-Chamber.swf
(And here are walkthroughs in case you wish to ruin the adventure ;)
-
Crimson Room walkthrough:
http://nordinho.com/vbull/showthread.php?t=3372
-
Viridian Room walkthrough:
http://www.thonky.com/viridian/
-
The Blue Chamber walkthrough
http://nordinho.com/vbull/showthread.php?t=3785
Still I strongly suggest you to try it yourself until you get stuck for long..nJoy!
(And in case you know another levels of this series do share them;)