.foo {
  @include waldo;
  content: 'baz';
}

.bar {
  content: 'baz';
  @include waldo;
}

.qux {
  content: 'baz';
  @include waldo;
  content: 'where';
}

.breakpoint {
  content: 'baz';

  @include breakpoint(500px) {
    content: 'waldo';
  }

  .foo {
    content: 'where';

    @include waldo;
  }
}