The invention relates to a modular system (10) for structuring or shaping spaces, surfaces, or the like, comprising a component assembly, which comprises at least two modular elements (12) and at least one connecting element (14, 15, 16), said modular element being designed as a box-shaped body, whose base has at least three corners, each corner forming a connecting structure for connecting the modular element to a connecting element, said connecting structure being designed as an arc-shaped contour of the corner together with a void adjacent to the contour, said connecting element forming a pin for each of the connecting structures to be connected, said pin being designed congruent with the void and in such a manner that the pin can be interlockingly inserted into the void, said connecting element forming a positioning device for positioning the connecting element on the modular element, said positioning device comprising an axis, said axis being designed congruent with the contour and in such a manner that the axis can be arranged on the contour.