function cpuChoice() {
let randomNumber
do {
randomNumber = Math.floor(Math.random() * tilesArr.length);
tiles[randomNumber].classList.add("green-mark", "marked")
} while (tiles[randomNumber].classList.contains("marked") == false);
}
function cpuChoice() {
let randomNumber
do {
randomNumber = Math.floor(Math.random() * tilesArr.length);
tiles[randomNumber].classList.add("green-mark", "marked")
} while (tiles[randomNumber].classList.contains("marked") == false);
}