"The Swiss engineer Heinz Isler started experimenting with ice just a few years after graduating from university.
He would hang nets, cloth, strings and balloons on trees, and support them from below with rods. They took on their natural form through their own weight and the wind. Sprayed with water, they iced over and formed self supporting structures.
Often, a millimeter thick layer of ice was enough to allow the supporting structure to be removed."
https://safetythird.wordpress.com/2011/04/18/heinz-isler-ice-structures/
He would hang nets, cloth, strings and balloons on trees, and support them from below with rods. They took on their natural form through their own weight and the wind. Sprayed with water, they iced over and formed self supporting structures.
Often, a millimeter thick layer of ice was enough to allow the supporting structure to be removed."
https://safetythird.wordpress.com/2011/04/18/heinz-isler-ice-structures/