layer at (0,0) size 800x600
  LayoutView at (0,0) size 800x600
layer at (0,0) size 800x600
  LayoutBlockFlow {HTML} at (0,0) size 800x600
    LayoutBlockFlow {BODY} at (0,0) size 800x600
      LayoutBlockFlow {DIV} at (0,0) size 800x18
        LayoutText {#text} at (0,0) size 468x17
          text run at (0,0) width 468: "Three green 16x16 pixel squares should appear below, stacked vertically."
      LayoutBlockFlow {DIV} at (0,18) size 18x18 [bgcolor=#FF0000] [border: (1px solid #000000)]
        LayoutImage {IMG} at (1,1) size 16x16
        LayoutText {#text} at (0,0) size 0x0
      LayoutBlockFlow (anonymous) at (0,36) size 800x36
        LayoutBR {BR} at (18,18) size 0x0
        LayoutText {#text} at (0,0) size 0x0
layer at (0,36) size 18x18
  LayoutIFrame {IFRAME} at (0,0) size 18x18 [bgcolor=#FF0000] [border: (1px solid #000000)]
    layer at (0,0) size 16x16
      LayoutView at (0,0) size 16x16
    layer at (0,0) size 16x16
      LayoutBlockFlow {HTML} at (0,0) size 16x16
        LayoutBlockFlow {BODY} at (0,0) size 16x16
          LayoutImage {IMG} at (0,0) size 16x16
layer at (0,54) size 18x18
  LayoutIFrame {IFRAME} at (0,18) size 18x18 [bgcolor=#FF0000] [border: (1px solid #000000)]
    layer at (0,0) size 16x16
      LayoutView at (0,0) size 16x16
    layer at (0,0) size 16x16
      LayoutBlockFlow {HTML} at (0,0) size 16x16
        LayoutBlockFlow {BODY} at (0,0) size 16x16
          LayoutImage {IMG} at (0,0) size 16x16