const addElement = () => {
   const typeNum = Math.round(Math.random()); //returns 0 or 1; 
   const newEle = document.createElement('div'); 

   if(typeNum === 0) { 
     configureWideElement(newEle);
   } else {
     configureTallElement(newEle); 
   }

   newEle.style.left = coordinates.x + 'px'; 
   newEle.style.top = coordinates.y + 'px'; 
   header.appendChild(newEle); 

 }