Really dumb question!

[Mike Silva]

So, my son and I are playing around with Python, esp. the turtle
module, and we can't figure out a way to stop the program!  Ctrl-C (in
any window) doesn't do it, and closing the Tk graphics window doesn't
do it (just opens up again and continues drawing).  This gets to be a
problem when he decides to draw 10 lines and types in 100 by mistake!

So, my really dumb question is -- how do we kill an executing program,
in particular one doing (turtle) graphics?!

Mike