Budding Idea

Hello everyone. I have an idea for a new project, now that finals are almost out of the way, but am having a little trouble on the programming aspect of the issue. I was inspired by a robot at a museum that could spell names by taking an input of your name, and then it would scan letter blocks and rearrange them. I was thinking sort of the same thing, but with Lego NXT. I would, instead of having blocks with letters, have actual 3 dimensional letters laying on the ground. You input the desired name and it will then scroll the the list of letters given to it, scan each one, and place it in another row by until the whole row is complete. First of course, when the program is started, it will calibrate itself by scanning all the letters into its memory. However, the scanning process is kind of sketchy. I've got the basic design down, I think, but when scanning, I don't quite understand the logic needed to store each scanned image as a separate letter and recall it when it when the input letters are read. Here's something like what I saw ...