DAVID MALAN: So what about a cat who doesn't like you petting him? Let's implement that. When green flag clicked, let's forever do the following. If the cat is touching the mouse pointer, then we'll do one thing. Else, we'll do something else. So we need a two-branch condition. And for our Boolean expression, we want to sense whether Scratch is touching the mouse pointer. And if so, this time we're going to have him play a sound of not Meow, the default but rather Lion, the roar. Else, we'll go ahead and have Scratch meow in the usual way. And thereafter, we'll give him a moment to catch his breath by waiting two seconds outside of that branch, no matter what sound he happens to make. Now we click that green flag. [MEOWING] There's that happy cat. But what if I try petting this cat as by moving my mouse pointer over him? [ROAR] Don't pet that cat.