[plt-scheme] htdp section 17.7

"3. This exercise separates those who have studied the design recipe  from 
those who haven't. Or those who will be great programmers from  those who 
will struggle.

Just do it. -- Matthias

P.S. Students who have never programmed before but follow the DR to  the dot 
tend to solve this problem in a couple of hours, max. They  are also usually 
girls but that's a coincidence."


...because girls are less likely than boys to have programmed before?