int facecount = 24;
int cface = 0;

int lastx;
int dir;

PImage faces[] = new PImage[facecount];
void setup(){
  size(80,80);  

  for(int i = 0; i < facecount; i++){
    String name = ""+(i+1)+".jpg";

    faces[i] = loadImage(name);
  }       


}

void draw(){
  image(faces[cface],0,0);
}

void mouseMoved(){
  doMouse();
}
void mouseDragged(){
  doMouse();
}

void doMouse(){

  int delta = mouseX - lastx;
  lastx = mouseX;
  int curdir = dir;
  if(delta != 0){
    curdir = delta / abs(delta);
  }
  if(dir != curdir){
    dir = curdir;
    cface++;
    if(cface >= facecount) {
      cface = 0;
    }
  }


}