#faux {
   position:relative;
   z-index:1;
   width:80%;
   margin:0 auto;
   overflow:hidden;
   background:#ffaf00;
}

#faux div {
   position:relative;
   float:left;
   width:30%;
}

#faux .main {left:35%}
#faux .supp1 {left:-28.5%}
#faux .supp2 {left:8.5%}


#faux:before,
#faux:after {
   content:"";
   position:absolute;
   z-index:-1;
   top:0;
   right:0;
   bottom:0;
   left:33.333%;
   background:#f9b6ff;
}

#faux:after {
   left:66.667%;
   background:#79daff;
}