I tried to improve this as best as I could. It shouldn't be that "jumpy" by adjusting some of the movement. Also, to circumvent Scratch's clone limit, I made each grain stamp itself and then delete itself if it touches another grain. You can have as many stamps as you want, just not clones.
I highly recommend creating another project. A grid-based pixel physics simulator is just a lot more effective than this because there won't be huge empty spaces between clones and you can have as many pixels as you want with minimal lag. In this, I can only have 300 clones max, and when they turn into stamps they can't be interacted with anymore.
