und: pink;
  height: 12px;
}
masonry-track {
  float: left;
  height: 100%;
  gap: 2px;
}
x,y,z,masonry-track { display: block; }
masonry-track > * { margin-bottom:2px; }
.last > masonry-track > :last-child { margin-bottom:0; }
masonry-track:nth-child(1) { width: 10px; }
masonry-track:nth-child(2) { width: 15px; margin-left:2px; }
masonry-track:nth-child(3) { width: 20px; margin-left:2px; }
</style></head>
<body>
<wrapper>
<div class="columns">
  <div class="grid first">
    <masonry-track><x></x><y></y><y>