Viewport <#document> at (0,0) content-size 800x600 children: not-inline
  BlockContainer <html> at (0,0) content-size 800x116 [BFC] children: not-inline
    BlockContainer <body> at (8,8) content-size 784x100 children: inline
      InlineNode <span>
        frag 0 from TextNode start: 0, length: 4, rect: [8,49 35.15625x17] baseline: 13.296875
            "foo "
        frag 1 from BlockContainer start: 0, length: 0, rect: [43.15625,8 100x100] baseline: 54.296875
        TextNode <#text>
        BlockContainer <span.thing> at (43.15625,8) content-size 100x100 inline-block [BFC] children: not-inline

ViewportPaintable (Viewport<#document>) [0,0 800x600]
  PaintableWithLines (BlockContainer<HTML>) [0,0 800x116]
    PaintableWithLines (BlockContainer<BODY>) [8,8 784x100]
      PaintableWithLines (InlineNode<SPAN>)
        TextPaintable (TextNode<#text>)
        PaintableWithLines (BlockContainer<SPAN>.thing) [43.15625,8 100x100]
