Placing the "if touching color red" block inside a "forever" loop makes the game check for the collision over and over again as the game is being played. If the player touches the color red at any point, it will move the player back to the starting position.
Here is how to change the color in the "touching color" block:
The player should be sent back to the start of the level if they touch the color red.
We will do this in the following way:
You may notice that the wall only blocks your movement when you are moving down. This is because we only added code that handles solid walls to our downward movement block.