A Trail of Bones

Time for a small project! In this checkpoint, you'll build whole programs on your own, using what you've learned in the first two lessons: walking and turning, picking up bones, and loops, nested ones too.

The exercises here are a bit different from the ones so far. The instructions say what the dog should do, not which blocks to use. There are many correct programs, so build the one that makes sense to you. If you get stuck, look back at the lesson where you learned what you need.

The project. It's Saturday, and the dog is going for a walk in the park. Over three exercises, it follows a trail of bones, crosses a hill and walks around the big lawn.

The block limit. Each exercise limits the number of blocks, and a program that lists every step one by one would have too many. That's on purpose. Before you start building, trace the path with your finger, find the parts that repeat and let loops repeat them.

The task. The dog's owner has laid a trail of bones on the path between the hedges. Along the first part of the path, there's a bone on every other tile, and after the corner, there's one on every tile. The dog starts at the top, facing down the screen, towards you.

A tip: remember the Left or Right? exercise. At the corner, think about which way the dog is facing before you choose a turn.