Four Python 3 scripts are included that demonstrate CTRW-on-a-streamline particle tracking on heterogeneous hydraulic conductivity fields. Syntax from console: >python gen_k_fields.py >python solve_flow_sparse.py {basic|smoothed} >python particle_tracking_numba.py {basic|smoothed|smoothednoctrw} >python vis_plume_btc.py <maximum time for breakthrough curve> Syntax in bold: type exactly. Syntax in curly braces: type only one of the literal strings shown separated by the pipe character, "|". Syntax in angle brackets: type a number whose definition is given in the brackets.