and then a miracle occurs

I finally had the opportunity, in my abstract algebra class Fall 2000, to use this phrase on an exam (the final, at that). I ended up with a B in the course.

A senior professor is reviewing the chalkboard of his junior colleague. He says, "I think you should be more explicit here in step two." He is pointing to a section of the board that says, in the middle of some complicated-looking equations, 'THEN A MIRACLE OCCURS...'.

It's available on a t-shirt at http://www.sciencecartoonsplus.com/gallery.htm ;
the cartoon itself is available in a close-up at http://www.aip.org/education/sps/miraclen.jpg .