<ul id="mrtc">
    <li class="m"><span></span></li>
    <li class="r"><span></span></li>
    <li class="t"><span></span></li>
    <li class="c"><span></span></li>
</ul>
#mrtc {
    margin: auto;
    overflow: hidden;
}
#mrtc::before {
    content: "";
    display: block;
    padding-top: 12.5%;
}
#mrtc li {
    float: left;
    display: block;
    width: 23%;
    margin: 0 1%;
    position: relative;
}
#mrtc li:before {
    content: "";
    display: block;
    padding-top: 50%;
}
#mrtc span {
    position: absolute;
    top: 0;
    right: 0;
    bottom: 0;
    left: 0;
    display: block;
}
#mrtc .m span {
    border: 2px solid #000;
    border-bottom: none;
    -webkit-border-top-right-radius: 10% 20%;
    -moz-border-top-right-radius: 10% 20%;
    border-top-right-radius: 10% 20%;
}
#mrtc .m span:before {
    content: "";
    position: absolute;
    top: 0;
    left: 50%;
    display: block;
    background: #000;
    width: 2px;
    height: 100%;
    margin-left: -1px;
}
#mrtc .r span {
    border: 2px solid #000;
    border-right: none;
    border-bottom: none;
    -webkit-border-top-left-radius: 10% 20%;
    -moz-border-top-left-radius: 10% 20%;
    border-top-left-radius: 10% 20%;
}
#mrtc .t span {
    background: #c00;
    width: 100%;
    height: 200%;
    -webkit-border-radius: 50%;
    -moz-border-radius: 50%;
    border-tradius: 50%;
    margin-top: -50%;
}
#mrtc .t span:before {
    content: "";
    position: absolute;
    top: 0;
    left: 50%;
    display: block;
    background: #fff;
    width: 2px;
    height: 100%;
    margin-left: -1px;
}
#mrtc .t span:after {
    content: "";
    position: absolute;
    top: 50%;
    left: 0;
    display: block;
    background: #fff;
    width: 100%;
    height: 2px;
    margin-top: -1px;
}   
#mrtc .c span {
    border: 2px solid #000;
    border-right: none;
    -webkit-border-top-left-radius: 10% 20%;
    -moz-border-top-left-radius: 10% 20%;
    border-top-left-radius: 10% 20%;
    -webkit-border-bottom-left-radius: 10% 20%;
    -moz-border-bottom-left-radius: 10% 20%;
    border-bottom-left-radius: 10% 20%;
}
@media screen and (min-width:560px){
    #mrtc li span {
        border-width: 3px !important;
    }
    #mrtc .m span:before,
    #mrtc .t span:before {
        width: 3px;
    }
    #mrtc .t span:after {
        height: 3px;
    }
}
@media screen and (max-width:320px){
    #mrtc li span {
        border-width: 1px !important;
    }
    #mrtc .m span:before,
    #mrtc .t span:before {
        width: 1px;
    }
    #mrtc .t span:after {
        height: 1px;
    }
}

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