CSS
body:before {
content: '';
position: absolute;
top: 0;
left: 0;
right: 0;
bottom: 0;
background-color:silver;
background-image:
radial-gradient(circle at 100% 150%, silver 24%, white 24%, white 28%, silver 28%, silver 36%, white 36%, white 40%, transparent 40%, transparent),
radial-gradient(circle at 0 150%, silver 24%, white 24%, white 28%, silver 28%, silver 36%, white 36%, white 40%, transparent 40%, transparent),
radial-gradient(circle at 50% 100%, white 10%, silver 10%, silver 23%, white 23%, white 30%, silver 30%, silver 43%, white 43%, white 50%, silver 50%, silver 63%, white 63%, white 71%, transparent 71%, transparent),
radial-gradient(circle at 100% 50%, white 5%, silver 5%, silver 15%, white 15%, white 20%, silver 20%, silver 29%, white 29%, white 34%, silver 34%, silver 44%, white 44%, white 49%, transparent 49%, transparent),
radial-gradient(circle at 0 50%, white 5%, silver 5%, silver 15%, white 15%, white 20%, silver 20%, silver 29%, white 29%, white 34%, silver 34%, silver 44%, white 44%, white 49%, transparent 49%, transparent);
background-size: 100px 50px;
z-index: -1;
transform: rotate(180deg)
}