orion
R.I.P.
I just got this link a couple of days ago. While it seems simple, it is both rather difficult and somewhat addictive. The note that came with it indicated that it was used as a dexterity training device for military pilots - if you last 18 seconds you're considered top ranking.
http://members.iinet.net.au/~pontipak/redsquare.html
http://members.iinet.net.au/~pontipak/redsquare.html