They are also surprisingly heavy. I remember years ago making a raised bed against a wall out of them, I only needed 3, when the chap forklifted the 2nd into the back of the Volvo (think it might have been an S70 back in the day) we looked at each other as the suspension settled and I decided to come back for the 3rd in a separate trip. The 2nd one was decided well seasoned.
Get them dropped as close to construction site as possible. They are easy to build with though, like lego just cross your joints if more than 1 layer. You can drill and hidden peg them quite easily for additional stability / security.
@Alex321 - might make things taste / smell of creosote though and potentially sticky to turn / sand?