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2. Snake bots

Let's build some snakes to get us thinking about permutations. Learn how to assemble different varieties of robots using a set number of segments, where each segment is used exactly once.

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Video transcript

- In the rest of this lesson, we're gonna look at a few other counting problems that come up when you try to make a large crowd of robots from a small bin of parts. We're gonna be building up to a really powerful formula that you can think of as a counting tool. (chimes ringing) To start, let's imagine snake-like robots. Let's call them Snake Bots. They are built as a sequence of segments where every segment must be used exactly once. For instance, if I'm building a three-segment Snake Bot, I might assemble the segments this way. Or I could do it this way. We'd again like to know: How many of these Snake Bots can I build? Remember, you have to account for every possibility. In the next exercise, you're gonna be asked to build all possible Snake Bots of length one through four. Go get 'em!