compass-style.org/content/examples/compass/helpers/using-extend-in-place-of-enumerate/stylesheet.scss
.example {
.base-class {
background-color: #aaaaaa;
border: 2px solid #777777;
margin: 1em;
}
@for $i from 2 through 4 {
.class-#{$i} {
@extend .base-class;
margin-left: 1em * ($i - 1);
}
}
}