Help! How do i make 3 tables across a landscape page

[pethl]

HI
I'm sure this is so obvious, but I've searched google for a day and can't find help or work it out.

How do I create three tables across a landscape page from left to right?
I can move the cursor to 'draw a circle' in the middle of the page but not to print the next table.

I've attached a file of what I am trying to recreate. I can do the left column and tables but can't understand how to make Prawn print the middle table in the middle of the sheet.

[gettalong]

Have you tried using a grid?

require 'prawn'
require 'prawn/table'

Prawn::Document.generate('tables.pdf') do·
  define_grid(columns: 3, rows: 1, gutter: 10)
  grid(0, 0).bounding_box do
    table([['a1', 'b'], ['c', 'd']])
  end
  grid(0, 1).bounding_box do
    table([['a2', 'b'], ['c', 'd']])
  end
  grid(0, 2).bounding_box do
    table([['a3', 'b'], ['c', 'd']])
  end
end

Result:

[pethl]

Thank you so much for taking the time to provide this answer. It work beautifully and I've regained my sanity.
I have many boxes in each grid column, but the simplicity of the grid makes that easy to manage.
Also I hadn't been understanding the 'bounding_box' clearly, but now through working your example and reading further, it makes perfect sense.