A = function(preserve_screen_top_of_cursor_node)
	-- translate Page to Surface
	while #Surface > 3 do table.remove(Surface) end  -- HACK
	local red = false
	for x=-1000,1000,100 do
		for y=-1000,1000,100 do
			add_thick_line({type='line', data={x,y, x+200,y+200, x,y+400}, r=red and 1 or 0,g=red and 0 or 0.5,b=0}, 10)
			red = not red
		end
	end
	compute_layout(Page, Page.x,Page.y, Surface, preserve_screen_top_of_cursor_node)
	-- continue the pipeline
	B(preserve_screen_top_of_cursor_node)
	-- TODO: ugly that we're manipulating editor objects twice
end