The beauty of Sass: creating loops directly in the stylesheet. In this one I've created a @for loop which is shifting the background sprite for each section. No need for a bunch of background-position declarations.

gistfile1.sass

& > section{
	float: left;
	margin-right: $lineheight;
	width: $wideColumn;
	background: transparent url(style/images/frontpage-icons.png) no-repeat left top;
	padding-top: $column;
				
	@for $i from 2 through 4 {

		&:nth-child(#{$i}){
			$i: $i - 1;
			background-position: -224px*$i top; 
		}
	}
}