Read here about tensegrity structures composed of seven struts, part of a series of pages organized by strut count.
Seven strut tensegrities are rare.
Mesh Bag with 7 struts by Snelson
Motro Form Finding
In "Structural Morphology Of Tensegrity Systems" Motro applies a free-form method of discovery to the generation of unusual tensegrity forms. The 7 strut is generated in a series from 4 to 8 struts. He wrote, "The process is started from a simple system and, next, more and more struts and cables are added step by step."
See Asian Journal Of Civil Engineering (Building And Housing) Vol. 10, No. 1 (2009) Pages 1-19