JSFiddle - React, Tailwind, and code Playground

HTML

<div class="containing">
    <div class="block1">block1</div>
    <div class="block2">block2</div>
    <div class="block3">block3</div>
    <div class="block4">block4</div>
</div>

CSS

.block1 {
    width: 400px;
    height: 400px;
    float: left;
    background-color: blue;
}
.containing {
    background-color: green;
}
.block2 {
    width: 200px;
    height: 200px;
    float: left;
    clear: left;
    background-color: red;
}
.block3 {
    width: 200px;
    height: 200px;
    float: left;
    background-color: yellow;
}
.block4 {
    width: 200px;
    height: 200px;
    float: left;
    background-color: orange;
}