.grid {
    display: flex;
	flex-wrap: wrap;
	border: solid black 5px;
	width: 300px;
	height: 300px;
	margin: auto;
	text-align: center;
	background-image: url("https://codehs.com/uploads/06d6eb8dee0b71f9319af161b5ec6632")
}

.grid div {
	width: 20px;
	height: 20px;
	margin: auto;
	text-align: center;
}

.shooter {
	background-image: url("https://codehs.com/uploads/d65258eb704e1aaf33cccfe17b098f64");
}

.invader {
	border-radius: 10000px;
	background-image: url("https://codehs.com/uploads/38b54a8e738aac36a5190783c0659f89");
}

.boom {
	background-image: url("https://codehs.com/uploads/e732893426f05e7e7f61ce48b78dbf1e");
}

.laser {
	background-image: url("https://codehs.com/uploads/e346825116c9baf61ce7f944bf0cfd12");
}