DAVID MALAN: Suppose we want Scratch to keep meowing on his own without my having to click that green flag again and again and again. Well, we can do that programmatically by using a loop. Let's start there. 

When green flag clicked, let's now go to the Control palette, where we can grab the Forever block. Now let's go to the Sound palette, where Play Sound awaits. And let's also give Scratch a moment to catch his breath. Under the control palette, we'll find Wait One Second. Now we click that green flag. 

[MEOWING] 

Hm. Not very natural. Meowing too fast. Let's stop. Let's this time increase that wait time from one second to two seconds and re-click that green flag. 

[MEOWING] 

Much more realistic.