Anyone remember holding 2 large mirrors parallel to each other and trying to see how far you could look into it. Well, this is the computer equivalent of that. We have 2 iMac's; 2007 24" AL is in the basement - wifes craft room, and late 2009 27" is in the 2nd floor loft area. Recently my wife has been using "Share Screen" to check email on the 27" while in the basement on her 24" iMac, knowing I was on the 27" iMac. She decided to get "cutsey" with me and took control of the cursor and typed me a note. So, me wanting to get into the fun I started Screen Sharing and weird things happened, like To Infinity and Beyond! Look here: I can't believe Apple left code so you could do this......try it yourself.