Yeah, it's directly inspired from Logo. Logo was great because you were immediately able to program, and immediately see the results on the screen. There wasn't any annoying procedures to do before you could start, no graphics packages to learn. That was my goal here -- to have as few barriers as possible between the person and the programming.

Why turtles? I don't know actually, I'm just following Logo's convention. Some implementations make it a little arrow - I prefer the turtle, especially because kids like it better. Though there isn't really a reason that a turtle should leave a trail, so maybe a slug would make more sense.