"Heinz Isler’s innovative methods for determining the shape of reinforced concrete shells first became widely known through his presentation of a paper entitled ‘New Shapes for Shells’... At that time reinforced concrete shells were a very popular form of construction worldwide. However, their forms were almost entirely those which could be described easily by geometrical and mathematical formulae e.g. barrel vaults, spherical domes, conoids, and constructed using relatively simple formwork as in the case of the straight boards used for hyperbolic paraboloid surfaces. ...[A] rounded mound of soil encircled by a trench and captioned “Form for a shell in concrete”; a stepped swimming pool of organic shape dug into the ground, labelled “Plastic shell as swimming pool”; and some rectangular ‘bubble’ shell roofs... illustrate the two of the three form-finding methods..."