A method for making a device for causing thrombosis of an aneurysm, wherein said device comprises a single elastic filament configurable between (i) an elongated, substantially linear configuration, and (ii) a longitudinally-contracted, substantially three-dimensional configuration, said method comprising:providing a sheet of shape memory material;producing a single filament, two-dimensional interim structure from said sheet of shape memory material;mounting said single filament, two-dimensional interim structure to a fixture so that said single filament, two-dimensional interim structure is transformed into said longitudinally-contracted, substantially three-dimensional configuration; andheat treating said single filament, two-dimensional interim structure while it is mounted to said fixture so as to produce said device in its longitudinally-contracted, substantially three-dimensional configuration.