=Bernie Cosell ...making the turtle scoot around the furniture...is more "fun"... ...and when the turtle hits the wall or the like...
This touches on some important educational themes missed so far: 1. at the elementary stages the most fun and memorable lessons always end with spectacular explosions 2. today, no one actually programs anything real from scratch; all code descends from "Hello World" For example, my son quite reasonably had zero interest in the baroqueries of HTML until I showed him how he could edit the sources of actual pages he browsed to get silly variants. Soon he wanted to craft his own "cool" home page. Hence, a good modern learning environment might be something like a fully functional fault-tolerant open source online video game, having modules perhaps designed with educational accessibility in mind. "Grasshopper, it is one thing to give the boss monster a pointy head by hacking its seed data, but to make more interesting duel combos you will want to know about the following algorithm..." Barring that, just take the cover off any program that does something even vaguely interesting. Inevitably the Joy of Hacking will seek ever more substantive objects of its affections--reflecting the psyche of the hacker, for good or ill. Who do you think writes viruses? (Ender's Game, anyone?<;-)