Using sin() to set speed

*/

​

// x-coordinate of current position

let x = 0;

// Angle of current speed

let a = 0;

// Speed at which we move along sine wave

let aspeed = 0.025;

​

function setup() {

  createCanvas(windowWidth, windowHeight);

​

}

​

function draw() {

  background(255);

  // Move along sine wave

  a+= aspeed;

  // Move with speed set by sine wave

  x+=sin(a)*(width/2)*aspeed;

​

  fill(0);

  noStroke();

  ellipse(x, height/2, 10, 10);

}