I. Print the first 6 pages.

II. Stop the printing process.

III. Flip the 6 pages long-ways.
(If the bottom of the image printed on the left side when it comes out the printer, make sure it is still on the left side after the paper has been flipped.)

IV.Print the next 6 pages.

V.Fold it in half, and hopefully you have a huge st∆pler.