Custom icons loop.

_icon.css.scss

// Position icon background image
@mixin icon($index, $y: 0, $width: 80px) {
  background-position: #{($index * -$width)} $y;
}

_icons.css.scss

$icon: users, megaphone, gavel, warning, chat, faq, pen-paper, document,
       pdf, checklist, scale, charts, calendar, search, mail, scroll,
       scroll-44, info, url;

.bopr-icon {
  background: image-url('bopr-icons.png') no-repeat 0 0;
  display: inline-block;
  height: 80px;
  width: 80px;

  @include hidpi(2) {
    background-image: image-url('bopr-icons_2x.png');
    background-size: auto 160px;
  }

  // Loop through icon names to build backgrounds
  @for $i from 1 through length($icon) {
    $index: $i - 1; // Pseudo zero-based index
    $class: nth($icon, $i); // Icon name

    &.#{$class} {
      @include icon($index); // Output background-position
    }
  }
}