Building this effect is simple! Download the sample files here.
1. First, create a text field. In this case, I gave it a variable name of "shuffle".
2. Convert the textfield to a movie clip, and name it "Random".
3. Right click the movie clip and go to its actions. Insert the following code:
shuffle = chr(random(25)+65);
4. Create duplicates of the movie clip.
That’s it! Run the movie, and you’ll see the effect above.