public void draw() {
// background(255);
fill(255);
rect(-4, -4, width + 4, height + 4);
for (int i = skaters.size() - 1; i >= 0; i--) {
Skater skater = (Skater) skaters.get(i);
// if (mousePressed) {
skater.trace(mouseX, mouseY); // blob[i].x etc.
println(i);
}
}
