Here one may find simple examples that show how to use "fix wall/ess" and "fix wall/region/ess" commands. --in.fix_wall_region: This input file uses Data_region file to setup a system of three particles colliding with a cubic region which its walls interact with particle with EES potential. To find out details of how to set parameters of "fix wall/region/ees" see documentaion. --in.fix_wall This input file uses Data_wall to confine a ellipsoidal particle between two EES walls to show how to use "fix wall/ees" command. For more details lookup LAMMPS's documentation.