Joomlanın J si ile değil ama css si ile ilgilenmişsiniz sanırım. yada herkesle aynı hayali kurmuşsunuz. acaba hangisi daha önce yapıldı?
http://templates.atarioyunlari.net/w.../wp1/style.css

.Sheet
{
  overflow: hidden;
  min-width:35px;
  min-height:35px;
  margin: 0 auto;
  position: relative;
  z-index: 0;
  width: 800px;
}
.Sheet-body
{
  position: relative;
  z-index: 0;
  margin: 8px;
}
.Sheet-tl
{
  position: absolute;
  overflow: hidden;
  z-index: -1;
  top: 0;
  left: 0;
  width: 17px;
  height: 17px;
  background-image: url('images/Sheet-s.png');
}
.Sheet-tr
{
  position: absolute;
  overflow: hidden;
  z-index: -1;
  top: 0;
  right: 0;
  width: 17px;
  height: 17px;
}
.Sheet-tr div
{
  position: absolute;
  z-index: -1;
  top: 0px;
  left: -17px;
  width: 34px;
  height: 34px;
  background-image: url('images/Sheet-s.png');
}
.Sheet-bl
{
  position: absolute;
  overflow: hidden;
  z-index: -1;
  bottom: 0;
  left: 0;
  width: 17px;
  height: 17px;
}
.Sheet-bl div
{
  position: absolute;
  z-index: -1;
  top: -17px;
  left: 0;
  width: 34px;
  height: 34px;
  background-image: url('images/Sheet-s.png');
}

http://www.parloio.net/templates/cow_new/css/style.css

.Sheet
{
  overflow: hidden;
  min-width:35px;
  min-height:35px;
  margin: 0 auto;
  position: relative;
  z-index: 0;
  width: 1000px;
}
.Sheet-body
{
  position: relative;
  z-index: 0;
  margin: 13px;
}
.Sheet-tl
{
  position: absolute;
  overflow: hidden;
  z-index: -1;
  top: 0;
  left: 0;
  width: 17px;
  height: 17px;
  background-image: url('../images/Sheet-s.png');
}
.Sheet-tr
{
  position: absolute;
  overflow: hidden;
  z-index: -1;
  top: 0;
  right: 0;
  width: 17px;
  height: 17px;
}
.Sheet-tr div
{
  position: absolute;
  z-index: -1;
  top: 0px;
  left: -17px;
  width: 34px;
  height: 34px;
  background-image: url('../images/Sheet-s.png');
}
.Sheet-bl
{
  position: absolute;
  overflow: hidden;
  z-index: -1;
  bottom: 0;
  left: 0;
  width: 17px;
  height: 17px;
}
.Sheet-bl div
{
  position: absolute;
  z-index: -1;
  top: -17px;
  left: 0;
  width: 34px;
  height: 34px;
  background-image: url('../images/Sheet-s.png');
}