RING code, which divides the 2D surface of the 3D expanding structure into N_elem elements. Here, a supernova remnant evolving into a homogeneous medium and stretched by Galactic shear is shown, with the colour depicting the surface density of elements (in M_⊙pc⁻²). The small round blue circle corresponds to the initial position and size of the remnant, and the elongated structure shows the age of 30 kyr.