[Tutor] Is there a way to force update the screen in tkinter?

[R. Alan Monroe]

I don't have the code here at home, but today I tried my first
experiments in Tkinter. I set up a button that fired off a function to
resize a rectangle in a canvas, with a for loop. Only problem is that
the screen isn't repainted in all the steps of the for loop - only at
the very end, when the rectangle is at its final, largest size. Can I
make it repaint DURING the loop?

Alan