void setup() {
   size(500, 500);
   background(255);

} // setup()

float x = 0;
void draw() {
   translate(50, height/2);
   fill(255, 46, 46);
   drawTruck(70, 30);
} // draw()

void drawTruck(float w, float h) {
   float x = 0, y = 0;
   float bodyW = w * 2 / 3, bodyH = h;
   float hoodW = w - bodyW, hoodH = h/2;
   float wheelD = bodyW * 0.3;
   noStroke();
   rect(x, y - h, bodyW, bodyH);
   
   rect(x + bodyW, y - hoodH, hoodW, hoodH);
   
   fill(0);
   triangle(x + bodyW, y - bodyH, x + bodyW, y - hoodH, x + bodyW + hoodW/2, y - hoodH);
   
   fill(0);
   circle(x + bodyW/2, y, wheelD);
   circle(x + bodyW + hoodW/2, y, wheelD);
} // drawTruck()

void mousePressed() {
   fill(random(255), random(255), random(255));
   drawTruck(random(60, 100), random(30, 70));
} // mousePressed()