Also, strokeWeight() and fill() never change. If you put them in draw(), then you are updating them every frame, so they should be put in setup() instead:

i just dont know is it where i am placing it?

1. PVector pos1, pos2;
2. PVector vel1, vel2;
3. 
   
4. void setup() {
5.   size(640, 480);
6. 
   
7.   // Static drawing settings.
8.   strokeWeight(4);
9.   fill(255, 255, 0);
10.   smooth();
11. 
    
12.   // Initial positions and velocities.
13.   pos1 = new PVector(random(0, width), random(0, height));
14.   pos2 = new PVector(random(0, width), random(0, height));
15.   vel1 = new PVector(random(-2.0, 2.0), random(-2.0, 2.0));
16.   vel2 = new PVector(random(-2.0, 2.0), random(-2.0, 2.0));
17. }
18. 
    
19. void draw() {
20.   background(255);
21. 
    
22.   // Update positions.
23.   pos1.x += vel1.x;
24.   pos1.y += vel1.y;
25.   pos2.x += vel2.x;
26.   pos2.y += vel2.y;
27. 
    
28.   // Check for collisions.
29.   if ( pos1.x < 2 || pos1.x > width-82 ) {
30.     pos1.x=constrain(pos1.x, 2, width-82);
31.     vel1.x*=-1;
32.   }
33.   if ( pos1.y < 2 || pos1.y > height-82 ) {
34.     pos1.y=constrain(pos1.y, 2, height-82);
35.     vel1.y*=-1;
36.   }
37. 
    
38.   // Draw first face.
39.   pushMatrix();
40.   translate(pos1.x, pos1.y);
41.   drawFace();
42.   popMatrix();
43. 
    
44.   // Draw second face.
45.   pushMatrix();
46.   translate(pos2.x, pos2.y);
47.   drawFace();
48.   popMatrix();
49. }
50. 
    
51. // Function to draw one face.
52. void drawFace() {
53.   ellipse(40, 40, 80, 80);
54.   point(30, 30);
55.   point(50, 30);
56.   arc(40, 40, 50, 50, radians(0), radians(180));
57. }

I have this but still says void? help again please :"(

PVector pos1, pos2;

PVector vel1, vel2;

void setup() {

  size(640, 480);

  // Static drawing settings.

  strokeWeight(4);

  fill(255, 255, 0);

  smooth();

  // Initial positions and velocities.

  pos1 = new PVector(random(0, width), random(0, height));

  pos2 = new PVector(random(0, width), random(0, height));

  vel1 = new PVector(random(-2.0, 2.0), random(-2.0, 2.0));

  vel2 = new PVector(random(-2.0, 2.0), random(-2.0, 2.0));

}

void draw() {

  background(255);

  // Update positions.

  pos1.x += vel1.x;

  pos1.y += vel1.y;

  pos2.x += vel2.x;

  pos2.y += vel2.y;

  // Check for collisions.

  if ( pos1.x < 2 || pos1.x > width-82 ) {

    pos1.x=constrain(pos1.x, 2, width-82);

    vel1.x*=-1;

  }

  if ( pos1.y < 2 || pos1.y > height-82 ) {

    pos1.y=constrain(pos1.y, 2, height-82);

    vel1.y*=-1;

  }

  if ( pos2.x < 2 || pos2.x > width-82 ) {

    pos2.x=constrain(pos2.x, 3, width-82);

    vel2.x*=-1;

  }

  if ( pos2.y < 2 || pos2.y > height-82 ) {

    pos2.y=constrain(pos2.y, 3, height-82);

    vel2.y*=-1;

    

    

  // Draw first face.

  pushMatrix();

  translate(pos1.x, pos1.y);

  drawFace();

  popMatrix();

  // Draw second face.

  pushMatrix();

  translate(pos2.x, pos2.y);

  drawFace();

  popMatrix();

}

// Function to draw one face.

void drawFace() {

  ellipse(40, 40, 80, 80);

  point(30, 30);

  point(50, 30);

  arc(40, 40, 50, 50, radians(0), radians(180));

  

}