JSFiddle - React, Tailwind, and code Playground

HTML

<div class="container">
    <div class="row">
        <div class="square"><span>1</span></div>
        <div class="square"><span>2</span></div>
    </div>
    <div class="row">
        <div class="square"><span>1</span></div>
        <div class="square"><span>2</span></div>
        <div class="square"><span>3</span></div>
        <div class="square"><span>4</span></div>
    </div>
    <div class="row">
        <div class="square"><span>1</span></div>
        <div class="square"><span>2</span></div>
        <div class="square"><span>3</span></div>
    </div>
    <div class="row">
        <div class="square"><span>1</span></div>
    </div>
</div>

CSS

.container {
    -webkit-transform: rotate(-45deg);
    -moz-transform: rotate(-45deg);
    -ms-transform: rotate(-45deg);
    transform: rotate(-45deg);
}

.row {
    float: left;
}

.row:nth-child(1) {
    margin-top: 110px;
}

.row:nth-child(3) {
    margin-top: 110px;
}

.row:nth-child(4) {
    margin-top: 220px;
}

.row .square {
    width: 100px;
    height: 100px;
    border: 5px solid #000;
    border-radius: 5px;
    background: yellow;
}

.square span {
    display: block;
    text-align: center;
    line-height: 100px;
    font-weight: bold;
    font-size: xx-large;
    -webkit-transform: rotate(45deg);
    -moz-transform: rotate(45deg);
    -ms-transform: rotate(45deg);
    transform: rotate(45deg);
}