<!DOCTYPE html>
<html>
<head>
<style>
.cube1 {
font-size: 4em;
width: 2em;
margin: 1.5em auto;
transform-style: preserve-3d;
transform: perspective(5cm) rotateX(-15deg) rotateY(30deg);
}
.cube2 {
font-size: 4em;
width: 2em;
margin: 1.5em auto;
transform-style: preserve-3d;
transform: perspective(10cm) rotateX(-15deg) rotateY(30deg);
}
.cube3 {
font-size: 4em;
width: 2em;
margin: 1.5em auto;
transform-style: preserve-3d;
transform: rotateX(-15deg) rotateY(30deg);
}
.side {
position: absolute;
width: 2em;
height: 2em;
background: rgba(100,100,100,0.3);
border: 1px solid red;
text-align: center;
line-height: 2em;
}
.front {transform: translateZ(1em);}
.top {transform: rotateX(90deg) translateZ(1em);}
.right {transform: rotateY(90deg) translateZ(1em);}
.left {transform: rotateY(-90deg) translateZ(1em);}
.bottom {transform: rotateX(-90deg) translateZ(1em);}
.back {transform: rotateY(-180deg) translateZ(1em);}
</style>
</head>
<body>