CSS画各种图形（五角星、吃豆人、太极图等）

 width: 0;
 height: 0;
 border-left: 70px solid transparent;
 border-right: 70px solid transparent;
 border-top: 100px solid red;
 border-radius: 50%;

 border-bottom: 100px solid red;
 border-left: 50px solid transparent;
 border-right: 50px solid transparent;
 height: 0;
 width: 100px;

 width: 150px;
 height: 100px;
 transform: skew(20deg);
 background: red;

#pentagon {
 position: relative;
 width: 54px;
 box-sizing: content-box;
 border-width: 50px 18px 0;
 border-style: solid;
 border-color: red transparent;
}
#pentagon:before {
 content: "";
 position: absolute;
 height: 0;
 width: 0;
 top: -85px;
 left: -18px;
 border-width: 0 45px 35px;
 border-style: solid;
 border-color: transparent transparent red;
}

#hexagon {
 width: 100px;
 height: 55px;
 background: red;
 position: relative;
}
#hexagon:before {
 content: "";
 position: absolute;
 top: -25px;
 left: 0;
 width: 0;
 height: 0;
 border-left: 50px solid transparent;
 border-right: 50px solid transparent;
 border-bottom: 25px solid red;
}
#hexagon:after {
 content: "";
 position: absolute;
 bottom: -25px;
 left: 0;
 width: 0;
 height: 0;
 border-left: 50px solid transparent;
 border-right: 50px solid transparent;
 border-top: 25px solid red;
}

#curvedarrow {
 position: relative;
 width: 0;
 height: 0;
 border-top: 9px solid transparent;
 border-right: 9px solid red;
 transform: rotate(10deg);
}
#curvedarrow:after {
 content: "";
 position: absolute;
 border: 0 solid transparent;
 border-top: 3px solid red;
 border-radius: 20px 0 0 0;
 top: -12px;
 left: -9px;
 width: 12px;
 height: 12px;
 transform: rotate(45deg);
}

#star-five {
 margin: 50px 0;
 position: relative;
 display: block;
 color: red;
 width: 0px;
 height: 0px;
 border-right: 100px solid transparent;
 border-bottom: 70px solid red;
 border-left: 100px solid transparent;
 transform: rotate(35deg);
}
#star-five:before {
 border-bottom: 80px solid red;
 border-left: 30px solid transparent;
 border-right: 30px solid transparent;
 position: absolute;
 height: 0;
 width: 0;
 top: -45px;
 left: -65px;
 display: block;
 content: '';
 transform: rotate(-35deg);
}
#star-five:after {
 position: absolute;
 display: block;
 color: red;
 top: 3px;
 left: -105px;
 width: 0px;
 height: 0px;
 border-right: 100px solid transparent;
 border-bottom: 70px solid red;
 border-left: 100px solid transparent;
 transform: rotate(-70deg);
 content: '';
}

#burst-12 {
 background: red;
 width: 80px;
 height: 80px;
 position: relative;
 text-align: center;
}
#burst-12:before, #burst-12:after {
 content: "";
 position: absolute;
 top: 0;
 left: 0;
 height: 80px;
 width: 80px;
 background: red;
}
#burst-12:before {
 transform: rotate(30deg);
}
#burst-12:after {
 transform: rotate(60deg);
}

#heart {
 position: relative;
 width: 100px;
 height: 90px;
}
#heart:before, #heart:after {
 position: absolute;
 content: "";
 left: 50px;
 top: 0;
 width: 50px;
 height: 80px;
 background: red;
 border-radius: 50px 50px 0 0;
 transform: rotate(-45deg);
 transform-origin: 0 100%;
}
#heart:after {
 left: 0;
 transform: rotate(45deg);
 transform-origin: 100% 100%;
}

#infinity {
 position: relative;
 width: 212px;
 height: 100px;
 box-sizing: content-box;
}
#infinity:before, #infinity:after {
 content: "";
 box-sizing: content-box;
 position: absolute;
 top: 0;
 left: 0;
 width: 60px;
 height: 60px;
 border: 20px solid red;
 border-radius: 50px 50px 0 50px;
 transform: rotate(-45deg);
}
#infinity:after {
 left: auto;
 right: 0;
 border-radius: 50px 50px 50px 0;
 transform: rotate(45deg);
}

#cut-diamond {
 border-style: solid;
 border-color: transparent transparentred transparent;
 border-width: 0 25px 25px 25px;
 height: 0;
 width: 50px;
 box-sizing: content-box;
 position: relative;
 margin: 20px 0 50px 0;
}
#cut-diamond:after {
 content: "";
 position: absolute;
 top: 25px;
 left: -25px;
 width: 0;
 height: 0;
 border-style: solid;
 border-color: red transparent transparent transparent;
 border-width: 70px 50px 0 50px;
}

#pacman {
 width: 0px;
 height: 0px;
 border-right: 60px solid transparent;
 border-top: 60px solid red;
 border-left: 60px solid red;
 border-bottom: 60px solid red;
 border-top-left-radius: 60px;
 border-top-right-radius: 60px;
 border-bottom-left-radius: 60px;
 border-bottom-right-radius: 60px;
}

#yin-yang {
 width: 96px;
 box-sizing: content-box;
 height: 48px;
 background: #eee;
 border-color: red;
 border-style: solid;
 border-width: 2px 2px 50px 2px;
 border-radius: 100%;
 position: relative;
}
#yin-yang:before {
 content: "";
 position: absolute;
 top: 50%;
 left: 0;
 background: #eee;
 border: 18px solid red;
 border-radius: 100%;
 width: 12px;
 height: 12px;
 box-sizing: content-box;
}
#yin-yang:after {
 content: "";
 position: absolute;
 top: 50%;
 left: 50%;
 background: red;
 border: 18px solid #eee;
 border-radius: 100%;
 width: 12px;
 height: 12px;
 box-sizing: content-box;
}

#lock {
 font-size: 8px;
 position: relative;
 width: 8em;
 height: 6em;
 border-radius: 1em;
 top: 5em;
 box-sizing: border-box;
 border: 3em solid red;
 margin: 0 0 6rem 0;
}
#lock:before {
 content: "";
 box-sizing: border-box;
 position: absolute;
 border: 1em solid red;
 width: 6em;
 height: 6em;
 left: 50%;
 margin-left: -3em;
 top: -7em;
 border-top-left-radius: 3em;
 border-top-right-radius: 3em;
}
#lock:after {
 content: "";
 box-sizing: border-box;
 position: absolute;
 border: 1em solid white;
 width: 1em;
 height: 2em;
 border-radius: .5em;
 left: 50%;
 top: -1em;
 margin-left: -1em;
}