JSFiddle - React, Tailwind, and code Playground

HTML

<div id="box">
    <div id="x"></div>
    <div id="y"></div>
</div>

CSS

#box {
    width: 100px;
    height: 100px;
    margin: 10px;
    background: #ededed;
    padding: 10px;
    
    /* ADD THE OVERFLOW */
    overflow-x: hidden;
    overflow-y: visible;
}

#x {
    width: 150px;
    height: 10px;
    background: #c1ffb2;
}

#y {
    width: 10px;
    height: 150px;
    background: #c4b2ff;
}