Sass
Sass mixin syntax:
@mixin column-count($nb-columns) {
  -webkit-column-count: $nb-columns;
  -moz-column-count: $nb-columns;
  column-count: $nb-columns;
}
// Calling the mixin:
.two-columns { @include column-count(2); }
Result:
.two-columns {
  -webkit-column-count: 2;
  -moz-column-count: 2;
  column-count: 2;
}