/* Step 1 */

* {
  margin:0;
}
body {
  margin:25px;
}
article {
  height:500px;
  width:100%;
  -webkit-column-count:3;
  -webkit-column-gap:50px;
  -webkit-column-fill:auto;
  -moz-column-count:3;
  -moz-column-gap:50px;
  -moz-column-fill:auto;
  -ms-column-count:3;
  -ms-column-gap:50px;
  -ms-column-fill:auto;
  column-count:3;
  column-gap:50px;
  column-fill:auto;
}

/* Step 2 */

article p {
  line-height:25px;
  font-size:1.125em;
  text-indent:1.5em;
}
article h1 {
  line-height:50px;
  font-size:2.25em;
}              

/* Step 3 */

html {
  height:100%; 
}
body {
  height:4%;
  margin:0 25px;
}
article {
  height:2500%;
  padding:25px 0;
  -webkit-box-sizing:border-box;
  -moz-box-sizing:border-box;
  -ms-box-sizing:border-box;
  box-sizing:border-box;
}

/* Step 4 */
                                                                                     
b {
  display:block;
  float:right;
}           
b:nth-of-type(odd) {
  height:100%;
  width:1%;
  clear:right;
  background-color:red;
}
b:nth-of-type(even) {
  height:250px;
  width:99%;
  background-color:silver;
}          
b:nth-of-type(2) {
  display:none;
}