.shape-ex6{
    width: 100px;
    height: 150px;
    background-color: #666;
    display: block;
    margin: 0 75px;
    position: relative;
}
.shape-ex6::before{
    content: '';
    width: 0;
    height: 0;
    display: block;
    border-left: 75px solid transparent;
    border-bottom: 150px solid #666;
    position: absolute;
    top: 0;
    right: 100%;
}
.shape-ex6::after{
    content: '';
    width: 0;
    height: 0;
    display: block;
    border-bottom: 150px solid #666;
    border-right: 75px solid transparent;
    position: absolute;
    top: 0;
    left: 100%;
}