cle.empty;
                p1.verlet_w = Wall.empty;
                
                % Inner loop over all other particles with higher ID
                for j = 1:drv.n_particles
                    p2 = drv.particles(j);
                    if (p1.id >= p2.id)
                        continue;
                    end
                    
                    % Check for existing interaction
                    if (any(p1.neigh_pid == p2.id))
                        % Get interaction object
               