RNA base pair cones native to pymol
Single cone style

Double cone style



requires installing python modules/libraries:
math
collections

download these files:

70S_RF2_A.pdb
oezipcodedraw_bp.py
start.pml


from command line
pymol start.pml

or
pymol
File -> open -> 70S_RF2_A.pdb
File -> run -> oezipcodedraw_bp.py
zdraw_bp all