I will try to show how to build with a beer bottle for scale. There should be in most photos a measuring device or a beer bottle or both.
Where's the beer bottle!
Tank House Ale appears in images 2 and 3. I think the bottle was in Ed's hand for all the rest!
Morning after inspection reveals that its quite straight for hand formed foam sheet. I've used this building process before and had good results. Clearly the beer bottle is only in the photos for scale reference but I did move it around a few times during the process Bill.