a {
  background-image: radial-gradient(ellipse farthest-corner at center, rgb(255,255,0), rgb(0,128,0));
}

b {
  background-image: radial-gradient(ellipse farthest-corner at center, rgb(255,255,0) 0, rgb(0,128,0) 100%);
}

c {
  background-image: radial-gradient(ellipse farthest-corner at center, rgb(255,255,0), rgb(0,128,0));
}

d {
  background-image: radial-gradient(circle farthest-corner at center, rgb(255,255,0), rgb(0,128,0));
}

e {
  background-image: radial-gradient(ellipse farthest-corner at center, rgb(255,0,0), rgb(255,255,0), rgb(0,128,0));
}

f {
  background-image: radial-gradient(ellipse farthest-side at left bottom, rgb(255,0,0), rgb(255,255,0) 50px, rgb(0,128,0));
}

g {
  background-image: radial-gradient(ellipse closest-side at 20px 30px, rgb(255,0,0), rgb(255,255,0), rgb(0,128,0));
}

h {
  background-image: radial-gradient(ellipse 20px 30px at 20px 30px, rgb(255,0,0), rgb(255,255,0), rgb(0,128,0));
}

i {
  background-image: radial-gradient(circle closest-side at 20px 30px, rgb(255,0,0), rgb(255,255,0), rgb(0,128,0));
}

j {
  background-image: radial-gradient(ellipse 20px 20px at 20px 30px, rgb(255,0,0), rgb(255,255,0), rgb(0,128,0));
}