String theory proposes that particles, described in the Standard Model as point-like entities, are in fact more like vibrating strings of energy. The different frequencies at which they vibrate through the fabric of space-time gives them their unique physical properties.
Gary Shiu, professor from the University of Wisconsin-Madison, proposes a model in which the shape of the extra spacial dimensions determines the properties of the universe, much in the same way the shape of a musical instrument determines its sound, meaning that string theory predicts that the particle masses and the forces exerted in the universe are in direct relation to the vibrating frequency of the string which, in turn, is given by the shape of the spatial dimensions.