Click the green flag and watch. The camera appears to be zooming in and out on an infinite grid of cats. But drag the slider to hide the mask, and you will see what is actually going on.
✿✿✿ Notes ✿✿✿ You will notice a slight "jump" when changing the mosaic effect. This can be made less noticeable by adjusting the position by a pixel or so, as I demonstrate in this remix: https://scratch.mit.edu/projects/547577564/ You might like the following projects, which look similar to this but use very different methods: "Squares Animation remix" by @kriblo: https://scratch.mit.edu/projects/421837480/ A remix by me, using a different method and different graphics: https://scratch.mit.edu/projects/422128523/ ✿✿✿ Credits ✿✿✿ Code by me. Cat by Scratch. The mask was inspired by the bars in @RobFarley74's awesome demo project Block Scroller: https://scratch.mit.edu/projects/447658801/