 Let's get back into the video game that you started working on earlier. This time, we're going to add animation to your game by writing functions to animate the target and danger sprites. Functions are a key part of animation in computer programs. A function that draws a static picture of your danger, for example, can place the sprite at a different location based on the input. When that input changes slightly based on time or user interaction, the sprite will appear to move. This is similar to the way that flipbook animations work, in which each page draws a static image that is changed by a small amount. When the pages are displayed quickly, the images appear to change smoothly. To make the target and danger sprites move across the screen, you will modify the update target and update danger functions. These functions will take in the current X coordinate of each sprite and return a new X coordinate. That is either greater than the previous X coordinate, if it wants to move from left to right, or less than the previous X coordinate, if it wants to move from right to left. At the end of this stage, your target and danger should move across the screen, but never return. That's a problem for another day.