<style>
.multicol {
  width: 500px;
  -moz-column-width: 100px;
  height: 100px;
  position: relative;
}
#clear {
  position: absolute;
}
.float {
  height: 300px;
}
</style>
<div class="multicol">
<div class="float">
<div class="multicol">
<div id="clear">
<div class="float">
<div class="multicol">
<div class="float">&nbsp;
</div>
<div class="multicol">
<div class="multicol">
<div class="float">a