HTML/CSS grid layout - html

Question

How could I change this grid layout so that the second row of blocks sit just below the corresponding block above it instead of forming a completely new row?
http://jsfiddle.net/AndyMP/wSvrN/
body {
margin-left: 0px;
margin-top: 0px;
margin-right: 0px;
margin-bottom: 0px;
}
#container {
position: absolute;
width: 60%;
left: 50%;
margin-left: -30%;
border: 1px dotted #333;
padding: 20px;
}
.box1 {
position: relative;
float: left;
width: 100px;
height: 150px;
background: #666;
margin: 0 15px 15px 0;
}
.box2 {
position: relative;
float: left;
width: 100px;
height: 200px;
background: #666;
margin: 0 15px 15px 0;
}
.box3 {
position: relative;
float: left;
width: 100px;
height: 100px;
background: #666;
margin: 0 15px 15px 0;
}
HTML
<div id="container">
<div class="box1"></div>
<div class="box3"></div>
<div class="box1"></div>
<div class="box2"></div>
<div class="box3"></div>
<div class="box2"></div>
<div class="box3"></div>
<div class="box2"></div>
<div class="box1"></div>
<div class="box1"></div>
<div class="box3"></div>
<div class="box2"></div>
</div>

Answer 1

You can not achieve this with Pure CSS. You have to use http://masonry.desandro.com/ for this.

Answer 2

Do you mean like this ?
http://jsfiddle.net/LtLrx/
CSS:
body {
margin-left: 0px;
margin-top: 0px;
margin-right: 0px;
margin-bottom: 0px;
}
#container {
position: absolute;
width: 60%;
left: 50%;
margin-left: -30%;
border: 1px dotted #333;
padding: 20px;
}
.contleft
{
float: left;
margin-right: 15px;
width: 30%;
position: relative;
height: 100%;
}
.contmiddle
{
float: left;
margin-right: 15px;
width: 30%;
position: relative;
height: 100%;
}
.contright
{
float: left;
width: 30%;
position: relative;
height: 100%;
}
.box1 {
position: relative;
float: left;
width: 100px;
height: 150px;
background: #666;
margin: 0 15px 15px 0;
}
.box2 {
position: relative;
float: left;
width: 100px;
height: 200px;
background: #666;
margin: 0 15px 15px 0;
}
.box3 {
position: relative;
float: left;
width: 100px;
height: 100px;
background: #666;
margin: 0 15px 15px 0;
}
HTML:
<div id="container">
<div class="contleft">
<div class="box1"></div>
<div class="box2"></div>
<div class="box3"></div>
<div class="box1"></div>
</div>
<div class="contmiddle">
<div class="box2"></div>
<div class="box1"></div>
<div class="box1"></div>
<div class="box2"></div>
</div>
<div class="contright">
<div class="box3"></div>
<div class="box1"></div>
<div class="box2"></div>
<div class="box1"></div>
</div>
</div>

Answer 3

I don't exactly get what you want. When I put that code into a test file, I get the following in my browser:
To me, it looks like the last two blocks are exactly below the other blocks in that same column.
A problem may be that you are specifying the width of the container as a percentage of the screen, and the width of the blocks as an absolute value.
Please comment, so I can make my answer clearer, this is all the info I can make from your question.