Add the ability to change the position, velocity, acceleration, and color of a particle from outside the class, i.e., add getter and setter methods.

class Particle {

private PVector location;

private PVector velocity;

private PVector acceleration;

private float radius;

Particle(PVector l) {

location = l.get();

acceleration = new PVector(0, 0.05);

velocity = new PVector(random(-1, 1), random(-2, 0));

radiusc = 23;

}

void update() {

velocity.add(acceleration);

location.add(velocity);

}

void display() {

drawCircle(radiusc);

}

void drawCircle(float radius) {

while (radius > 2) {

noStroke();

fill(10*radius, 75);

ellipse(location.x, location.y, radius, radius);

radius *= 0.75;

}

}

}