layer at (0,0) size 800x600
  LayoutView at (0,0) size 800x600
layer at (0,0) size 800x48
  LayoutBlockFlow {HTML} at (0,0) size 800x48
    LayoutBlockFlow {BODY} at (8,8) size 784x32
      LayoutBlockFlow {DIV} at (0,0) size 64x32
        LayoutText {#text} at (0,0) size 32x16
          text run at (0,0) width 32: "x "
        LayoutInline {SPAN} at (0,0) size 48x32
          LayoutText {#text} at (32,0) size 48x32
            text run at (32,0) width 16: "y"
            text run at (0,16) width 16: "z"
        LayoutText {#text} at (16,16) size 32x16
          text run at (16,16) width 32: " a"
selection start: position 5 of child 0 {#text} of child 3 {DIV} of body
selection end:   position 2 of child 2 {#text} of child 3 {DIV} of body