<!DOCTYPE html>
<html>
<body>
<style>
    div {
        border: 5px solid black;
    }
</style>
<div style="display: flex; height: 300pt; justify-content: flex-start; align-items: flex-start; background-color: gray">
    <div style="width: 50pt; height: 50pt; background-color: green"></div>
    <div style="width: 50pt; height: 50pt; background-color: red"></div>
    <div style="width: 50pt; height: 50pt; background-color: blue"></div>
    <div style="width: 50pt; height: 50pt; background-color: yellow"></di