The 11th night bonfires have fascinated me for a long time, and the regional variations in the design. In the estate near where I grew up they build the fires with a very wide base and the fire is never that tall. The best way to desribe it would be like a cake.
On the other side of town, they go for the more triangular traditional shape.
In Belfast the competition between rival areas has resulted in some enormous structures, like those being built on the Lower Newtownards Rd at the moment. These usually take the form of a triangular base and then an ever decreasing stack of pallets. How they get the pallets on the top is beyond me.
I came across this report : The Northern Ireland Used Tyre Survey, where 30% of all used tyres were found to be removed to an unknown destination. Aye dead on!!