Procedure question from newbie

["Russell, Ken" <krussell@xxxxxxxxxxxxxxx>]

Although I am not exactly new to MicroWorlds, it's been over 10 years since I 
used LogoWriter and MicroWorlds is much more powerful than the LogoWriter I 
remember.

I am creating an activity for my students where they have the turtle draw a 
maze and then "drive" the turtle though it. Creating the maze using basic 
turtle graphics is easy. What I need to figure out is how I can make the 
"walls" that are drawn by the turtle become barriers to turtle movement. After 
the turtle draws the walls, he returns home where he can start his journey 
though the maze. I need a procedure where if the turtle crosses one of the 
walls, it stops at the wall (and/or maybe returns to home?). Basically, if he 
hits a wall, the turtle needs to start the maze over.

Is there a way to so this? Can he sense the color when he crosses it and does 
not land on it? Is there a bit of code in a published activity that is an 
example of this kind of procedure so I can adapt it? Do I need to figure out 
another way to do it?

Thanks in advance for your help!

Ken Russell
Bellingham Schools