Ошибка: Cannot read property 'classList' of null

function create() { 
 
	function getRandom() { 
		return Math.round(Math.random()*(mainArr.length-1)) 
	} 
	 
 
	currentFigure = getRandom(); 
 
	figureBody = [ 
		document.querySelector('[posX = "${x}"][posY = "${y}"]'), 
		document.querySelector('[posX = "${x + mainArr[currentFigure][0][0]}"][posY = "${y + mainArr[currentFigure][0][1]}"]'), 
		document.querySelector('[posX = "${x + mainArr[currentFigure][1][0]}"][posY = "${y + mainArr[currentFigure][1][1]}"]'), 
		document.querySelector('[posX = "${x + mainArr[currentFigure][2][0]}"][posY = "${y + mainArr[currentFigure][2][1]}"]'), 
	] 
 
	for (let i = 0; i < figureBody.length; i++) { 
		figureBody[i].classList.add('figure'); 
	} 
}