CSS
.gradient {
width: 500px;
height: 500px;
background:
linear-gradient(to bottom, #000 0px, #f00 30px, transparent 30px, transparent 60px),
linear-gradient(to bottom, #0f0 30px, #00f 60px);
background-size: 100% 60px;
background-repeat: repeat-y;
}