Generated by SassMeister.com.

SassMeister-input.scss

// ----
// Sass (v3.3.5)
// Compass (v1.0.0.alpha.18)
// ----

$sprite-item--list: en-gb sp af;
$sprite-item--size: 50px;
 
 @mixin sprite($sprite-item--offset) {
	$sprite-item--offset: $sprite-item--offset - 1;
	background-position: $sprite-item--size*-$sprite-item--offset 0;
}
 
@for $i from 1 through length($sprite-item--list) {
  $sprite-item: nth($sprite-item--list, $i);
  .#{$sprite-item} {
    @include sprite($i);
  }
}

SassMeister-output.css

.en-gb {
  background-position: 0px 0;
}

.sp {
  background-position: -50px 0;
}

.af {
  background-position: -100px 0;
}