$number: 1;  // .5, 100px, 1em
$string: bold; // "./~", relative
$color: red; // #FFFF00, rgba(0,0,0,.1)
$boolean: true;
$null: null;
$list: orange, royalblue, yellow; // 배열과 비슷
$map: (
	o: orange,
	r: royalblue,
	y: yellow
); // 객체와 비슷

@each $c in $list {
	.box {
		color: $c;
	}
}

@each $key, $value in $map {
	.box-#{$key} {
		color: $value;
	}
}