prawn：Prawn::Document::ColumnBox.new

everyday Ruby 
#!/usr/bin/env ruby

require "prawn"

pdf = Prawn::Document.new


p Prawn::Document::ColumnBox.new(pdf, [0, 0])

で、

#<Prawn::Document::ColumnBox:0xb7b549d0 @columns=3, @x=0, @spacer=12, @width=nil, @parent=#<Prawn::Document:0xb7b5653c @current_page=#<Prawn::Reference:0xb7b54660 @data={:Parent=>#<Prawn::Reference:0xb7b54a34 @data={:Count=>1, :Kids=>[#<Prawn::Reference:0xb7b54660 ...>], :Type=>:Pages}, @gen=0, @on_encode=nil, @identifier=2, @compressed=false>, :MediaBox=>[0, 0, 612.0, 792.0], :Contents=>#<Prawn::Reference:0xb7b546b0 @data={:Length=>0}, @stream="0.000 0.000 0.000 rg\n0.000 0.000 0.000 RG\nq\n", @gen=0, @on_encode=nil, @identifier=4, @compressed=false>, :Type=>:Page}, @gen=0, @on_encode=nil, @identifier=5, @compressed=false>, @font_size=12, @version=1.3, @bounding_box=#<Prawn::Document::BoundingBox:0xb7b546ec @x=36, @width=540.0, @parent=#<Prawn::Document:0xb7b5653c ...>, @height=720.0, @y=756.0>, @root=#<Prawn::Reference:0xb7b54a0c @data={:Pages=>#<Prawn::Reference:0xb7b54a34 @data={:Count=>1, :Kids=>[#<Prawn::Reference:0xb7b54660 @data={:Parent=>#<Prawn::Reference:0xb7b54a34 ...>, :MediaBox=>[0, 0, 612.0, 792.0], :Contents=>#<Prawn::Reference:0xb7b546b0 @data={:Length=>0}, @stream="0.000 0.000 0.000 rg\n0.000 0.000 0.000 RG\nq\n", @gen=0, @on_encode=nil, @identifier=4, @compressed=false>, :Type=>:Page}, @gen=0, @on_encode=nil, @identifier=5, @compressed=false>], :Type=>:Pages}, @gen=0, @on_encode=nil, @identifier=2, @compressed=false>, :Type=>:Catalog}, @gen=0, @on_encode=nil, @identifier=3, @compressed=false>, @background=nil, @pages=#<Prawn::Reference:0xb7b54a34 @data={:Count=>1, :Kids=>[#<Prawn::Reference:0xb7b54660 @data={:Parent=>#<Prawn::Reference:0xb7b54a34 ...>, :MediaBox=>[0, 0, 612.0, 792.0], :Contents=>#<Prawn::Reference:0xb7b546b0 @data={:Length=>0}, @stream="0.000 0.000 0.000 rg\n0.000 0.000 0.000 RG\nq\n", @gen=0, @on_encode=nil, @identifier=4, @compressed=false>, :Type=>:Page}, @gen=0, @on_encode=nil, @identifier=5, @compressed=false>], :Type=>:Pages}, @gen=0, @on_encode=nil, @identifier=2, @compressed=false>, @page_layout=:portrait, @margins={:top=>36, :bottom=>36, :left=>36, :right=>36}, @page_content=#<Prawn::Reference:0xb7b546b0 @data={:Length=>0}, @stream="0.000 0.000 0.000 rg\n0.000 0.000 0.000 RG\nq\n", @gen=0, @on_encode=nil, @identifier=4, @compressed=false>, @skip_encoding=nil, @info=#<Prawn::Reference:0xb7b54a70 @data={:Creator=>"Prawn", :Producer=>"Prawn"}, @gen=0, @on_encode=nil, @identifier=1, @compressed=false>, @stroke_color="000000", @page_size="LETTER", @y=756.0, @fill_color="000000", @text_options={}, @compress=false, @objects=[#<Prawn::Reference:0xb7b54a70 @data={:Creator=>"Prawn", :Producer=>"Prawn"}, @gen=0, @on_encode=nil, @identifier=1, @compressed=false>, #<Prawn::Reference:0xb7b54a34 @data={:Count=>1, :Kids=>[#<Prawn::Reference:0xb7b54660 @data={:Parent=>#<Prawn::Reference:0xb7b54a34 ...>, :MediaBox=>[0, 0, 612.0, 792.0], :Contents=>#<Prawn::Reference:0xb7b546b0 @data={:Length=>0}, @stream="0.000 0.000 0.000 rg\n0.000 0.000 0.000 RG\nq\n", @gen=0, @on_encode=nil, @identifier=4, @compressed=false>, :Type=>:Page}, @gen=0, @on_encode=nil, @identifier=5, @compressed=false>], :Type=>:Pages}, @gen=0, @on_encode=nil, @identifier=2, @compressed=false>, #<Prawn::Reference:0xb7b54a0c @data={:Pages=>#<Prawn::Reference:0xb7b54a34 @data={:Count=>1, :Kids=>[#<Prawn::Reference:0xb7b54660 @data={:Parent=>#<Prawn::Reference:0xb7b54a34 ...>, :MediaBox=>[0, 0, 612.0, 792.0], :Contents=>#<Prawn::Reference:0xb7b546b0 @data={:Length=>0}, @stream="0.000 0.000 0.000 rg\n0.000 0.000 0.000 RG\nq\n", @gen=0, @on_encode=nil, @identifier=4, @compressed=false>, :Type=>:Page}, @gen=0, @on_encode=nil, @identifier=5, @compressed=false>], :Type=>:Pages}, @gen=0, @on_encode=nil, @identifier=2, @compressed=false>, :Type=>:Catalog}, @gen=0, @on_encode=nil, @identifier=3, @compressed=false>, #<Prawn::Reference:0xb7b546b0 @data={:Length=>0}, @stream="0.000 0.000 0.000 rg\n0.000 0.000 0.000 RG\nq\n", @gen=0, @on_encode=nil, @identifier=4, @compressed=false>, #<Prawn::Reference:0xb7b54660 @data={:Parent=>#<Prawn::Reference:0xb7b54a34 @data={:Count=>1, :Kids=>[#<Prawn::Reference:0xb7b54660 ...>], :Type=>:Pages}, @gen=0, @on_encode=nil, @identifier=2, @compressed=false>, :MediaBox=>[0, 0, 612.0, 792.0], :Contents=>#<Prawn::Reference:0xb7b546b0 @data={:Length=>0}, @stream="0.000 0.000 0.000 rg\n0.000 0.000 0.000 RG\nq\n", @gen=0, @on_encode=nil, @identifier=4, @compressed=false>, :Type=>:Page}, @gen=0, @on_encode=nil, @identifier=5, @compressed=false>], @margin_box=#<Prawn::Document::BoundingBox:0xb7b546ec @x=36, @width=540.0, @parent=#<Prawn::Document:0xb7b5653c ...>, @height=720.0, @y=756.0>>, @height=nil, @y=0, @current_column=0>