let SLIDEINDEX = 0;
showSlide(SLIDEINDEX)
function showSlide(index) {
let picture = document.querySelectorAll('.pictures');
if (index >= picture.length) SLIDEINDEX = 0;
if (index < 0) SLIDEINDEX = picture.length -1;
for (let i = 0; i < picture.length; i++) {
picture[i].style.display = 'none';
}
picture[SLIDEINDEX].style.display = "block";
}
setInterval(function(){showSlide(++SLIDEINDEX)}, 5000);