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Link to the project or level: [(Game Lab - Code.org)] What I expect to happen: [Student would like to know how to make the background undulate.] What actually happens: [Neither the student nor I could figure it out.] What I’ve tried: [I looked at the Example solution, but can’t figure out what part of the code makes the background move in the way. Possibly it is set when they create the animation?]
Welcome to the forum! Your guess is correct that the undulation you are seeing is part of the animation itself (and not in the code). If you click on the Animation tab and look at the various animations, you can see how they are created. They are similar to animated gif’s where each image has multiple frames that are slightly different one from another.
Much like flipbook style animation, the frames rotate rapidly from one to the next simulating an animation.
Students are usually pretty good about exploring the animation tab and figuring that kind of stuff out. Usually, they would start with one image and then duplicate it (bottom right hander corner of the thumbnail sketch has a duplication icon. They can then use the eraser tool (to erase pixels), the pen tool (to add pixels) and the eyedropper tool (to get colors from the existing image before they add pixels with the pen tool).
Another helpful tool is the move tool (hand icon) as you can use it to move the entire drawing (ie up one pixel to imitate a jump, for example).
The paint bucket tools can be used to change colors (color changing animations), etc.
I found if I show the students a few things and encourage them to explore the various tools, they will get the hang of it quickly and will come up with stuff more imaginative than you would imagine… (They have more patience than I do with these kinds of things … I can’t focus on a project like that for as long as some of them will do it).