Caden, the four year old, runs into the room, "Look Mommy, I did the Rubik's Cube."
"Yes," she says, proudly holding up the cube and showing that indeed one side has been solved.
"Wow, you did that all on your own?"
"Well," she says looking down a little, "Reilly helped me move one of the stickers."
Now try explaining why doing that may make it insoluble, i.e. you do all the other sides and try as you might there are two or three squares that you can't get into place.
Posted by Paul Morriss on 2007-11-19
Posted by Justin Watt on 2007-11-18