Untitled

dabblet.css

.icon {
	display: block;
	position: relative;
	width: 6px;
	height: 6px;
	background-color: #FFF;
	border: 2px solid black;
	border-radius: 5px;
}

.icon::before {
	content: '';
	z-index: -1;
	position: absolute;
	top: 2px;
	left: -4px;
	width: 14px;
	height: 2px;
	background-color: #000;
}


.icon::after {
	content: '';
	z-index: -1;
	position: absolute;
	top: -4px;
	left: 2px;
	width: 2px;
	height: 14px;
	background-color: #000;
}

dabblet.html

<span class="icon"></span>

settings.json

{"view":"split-vertical","fontsize":"100","seethrough":"","prefixfree":"1","page":"all"}