<div class="box">
	<p>幅:100px／高さ:100px</p>
	<div class="example sizeL"></div>
</div>

<div class="box">
	<p>幅:60px／高さ:60px</p>
	<div class="example sizeM"></div>
</div>

<div class="box">
	<p>幅:0／高さ:0</p>
	<div class="example sizeS"></div>
</div>

* {
	box-sizing: border-box;
}
body {
	min-height: 100vh;
	margin: 0;
	padding: 0;
	display: flex;
	justify-content: center;
	align-items: center;
}
.box {
	text-align: center;
}
.box:not(:last-of-type) {
	margin-right: 5%;
}
.example {
	width: 100px;
	height: 100px;
	border-top: 20px solid #a0dde2;
	border-left: 20px solid #e2a0b4;
	border-right: 20px solid #eec496;
	border-bottom: 20px solid #a0e2c2;
	display: inline-block;
}
.example.sizeL {
	width: 100px;
	height: 100px;
}
.example.sizeM {
	width: 60px;
	height: 60px;
}
.example.sizeS {
	width: 0;
	height: 0;
}