JSFiddle - React, Tailwind, and code Playground
HTML
<div id="container">
</div>
CSS
#container {
background-color: #789;
display: grid;
grid-template-columns: 25% 25% 25% 25%;
grid-template-rows: 25% 25% 25% 25%;
width: 200px;
height: 200px;
padding: 2px;
}
#container button {
margin: 2px;
}
JavaScript
let container = document.getElementById("container");
for (let i=1; i<=16; i++) {
let butt = document.createElement("button");
butt.innerHTML = i;
container.appendChild(butt);
}