Wave your mouse to make them jump. Change the number of jumpers with the slider. See what happens when you press 'r'.
I wanted to make something for the Getting Unstuck prompt about jumping (but ultimately also incorporated music and randomness). I didn't know exactly what I wanted it to be like, but I thought it would be fun to have lots of interactive things jumping. So I started with some clones and went from there. While making this, I experimented with different ways to make a smooth jumping effect. At first, I was doing it the "math" way, with a parabolic equation. But I found that confusing in terms of getting the effect that I wanted, and I knew that the code would be big and hard to look at! So I switched to the "physics" way, by having a y velocity that I constantly changed with gravity, and repeatedly changing the y position. Of course, either would work (and they're very related) but the "physics" version felt more like I was using the affordances of Scratch and was easier for me to think about, so I stuck with that. I also added "play note" sounds. I experimented with different scales, using lists, and ultimately landed on Bb blues.