Hey, I made that
And it is what I use in all of my first person games and examples, it is a very good non-python method.
By the way, the 0 in there, when the variables are being multiplied by 0, it is not actually 0, its a very small number more like 0.001 for vertical or 0.0007 for horizontal that just appear as 0 because Alice does not want to display such a small number. If you just put "0" in for that number, you will find that the code will not work and you will just be moving the mouse with no results.
Check out my best projects so far and please comment:
Tic-Tac-Toe 2.0 ................... http://www.alice.org/community/showthread.php?t=3548
Alice Paint ........................... http://www.alice.org/community/showthread.php?p=23408
Real-Time Clock .................. http://www.alice.org/community/showthread.php?p=12725
Maze Game ......................... http://www.alice.org/community/showthread.php?t=4301