<div class="darkslateblue"></div>
<div class="mediumorchid"></div>
<div class="seagreen"></div>
<div class="steelblue"></div>

// colors
@colors: darkslateblue mediumorchid seagreen steelblue;

// loop definition
.backgrounds(@list, @i: 1) when (@i <= length(@list)) {
  // extract the right color from the list
  @color: extract(@list, @i);
  
  // apply the background to the selector
  .@{color} {
    background: @color;
  }
  
  // recursive call for the next color
  .backgrounds(@list, @i + 1);
}

// application
.backgrounds(@colors);


// styles
body {
  display: flex;
}

div {
  flex: 1 1 auto;
  height: 100vh;
}