This Scratch project shows you the difference between what the "set" and "change" code blocks do. Click the green flag and try clicking on the code blocks, and see how the "my variable" and Cat's x position change. (Note: In this demo, you can't change the numbers in the white text field.) The "set" blocks set the value exactly to the number in the white text field. The "change" blocks increases or decreases the value based on the current value.