exec('range_fun.sci');  /// @@prerequisite  affectations

TCL_SetVar('a','3');  /// \sleftarrow{\normalfont setting \verb+a+ to \verb+3+ in Tcl/Tk}
TCL_SetVar('b','2');  /// \sleftarrow{\normalfont setting \verb+b+ to \verb+3+ in Tcl/Tk}
plot3d_tcl();