Would you like to type a rectangle / cone only using css? As in the image below:
I need to use the background of a div or button, but it has to be in that format.
.trapezio {
border-top: 50px solid blue;
border-left: 25px solid transparent;
border-right: 25px solid transparent;
height: 0;
width: 50px;
}
<div class="trapezio"></div>
Here's an excellent reference on how to draw shapes using only or CSS