        filename                        format
----------------------------------------------------------
ref_simulation.frc_0.xyz                  xyz
ref_simulation.frc_1.xyz                  xyz
ref_simulation.frc_2.xyz                  xyz
ref_simulation.frc_3.xyz                  xyz
ref_simulation.frc_spring_0.xyz           xyz
ref_simulation.frc_spring_1.xyz           xyz
ref_simulation.frc_spring_2.xyz           xyz
ref_simulation.frc_spring_3.xyz           xyz
