background: radial-gradient(yellow, green);

background: radial-gradient(circle, yellow, green);

background: radial-gradient(circle closest-side, yellow, green);

background: radial-gradient(at top left, yellow, green);

background: repeating-radial-gradient(#8d0, #0d0 10px, #9f0 10px, #0f0 20px);

HTML Dog