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  LayoutView at (0,0) size 800x600
layer at (0,0) size 800x600
  LayoutBlockFlow {HTML} at (0,0) size 800x600
    LayoutBlockFlow {BODY} at (8,8) size 784x584
      LayoutText {#text} at (0,0) size 287x19
        text run at (0,0) width 287: "You should see a 100x100 green square below."
      LayoutText {#text} at (0,0) size 0x0
layer at (50,50) size 100x500 backgroundClip at (50,50) size 100x100 clip at (50,50) size 100x100
  LayoutBlockFlow (positioned) {DIV} at (50,50) size 100x500 [bgcolor=#008000]