I am so interested in a product I have been reading about that seems as if it will vastly improve options for design and construction in the garden (amongst other things). Sing honeycomb products are a green product that will cut down on cost and weight (and therefore transportation resources) and manufacturing while increasing flexibility for its applications.
The product is a core that can be used inside concrete, wood, plastic, and metals. Using it as the core of concrete makes a bench/ table/deck/counter top/etc. such as this, 10% of the solid weight of the same sized bench, it is also stronger, less expensive and highly insulated.
Here is a bench with wood veneer
Interestingly, these guys are so confident of this product, that if you have an idea to use the product in a new interesting way, they will provide you with free materials for construction (see applications here).