codingMath03b

float centerY, centerX, offset, speed, angle;
float baseRadius;

void setup() {
  size(400, 400);
  noStroke();
  fill(0);

  centerY = height / 2;
  centerX = width / 2;
  offset = 50; // amplitude
  speed = 0.1;
  angle = 0;

  baseRadius = 100;
}

void draw() {
  background(255); // clear canvas

  float radius = baseRadius + (sin(angle) * offset);

  ellipse(centerX, centerY, radius, radius);

  angle += speed;
}