This example is for Processing 3+. If you have a previous version, use the examples included with your software. If you see any errors or have suggestions, please let us know.

Translate.

The translate() function allows objects to be moved to any location within the window. The first parameter sets the x-axis offset and the second parameter sets the y-axis offset.

 
float x, y;
float dim = 80.0;

void setup() {
  size(640, 360);
  noStroke();
}

void draw() {
  background(102);
  
  x = x + 0.8;
  
  if (x > width + dim) {
    x = -dim;
  } 
  
  translate(x, height/2-dim/2);
  fill(255);
  rect(-dim/2, -dim/2, dim, dim);
  
  // Transforms accumulate. Notice how this rect moves 
  // twice as fast as the other, but it has the same 
  // parameter for the x-axis value
  translate(x, dim);
  fill(0);
  rect(-dim/2, -dim/2, dim, dim);
}