CSS: Make two floating elements overlap

Question

I have two divs within a container. One floats left and one floats right. Both are about 60% as wide as the container and are designed such that they overlap in the middle (

Answer 1

Make container bigger so both fit. Then use position relative and left: -100px or whatever on the one on the right.

Answer 2

How about pulling the right div with negative margin. Something like this?

<div id="container">
    <div id="left">left</div>
    <div id="right">right</div>
</div>

#container {
    position: relative;
    width: 400px;
    height: 110px;
    background-color: #eee;
}

#left {
    width: 250px;
    height: 100px;
    border: 1px solid green;
    float: left;
}

#right {
    position: relative;
    float: right;
    width: 250px;
    height: 100px;
    top: -100px;
    border: 1px solid red;
}