Original image
  1. drop-shadow(2px 2px 2px)
  2. drop-shadow(0.5em 0.33em 0.5em red)
  3. drop-shadow(-0.5em -0.25em 3px gray)
  4. drop-shadow(0 0 0.5em yellow)
    drop-shadow(0.5em 0.75em 30px gray)