As the sample from David Nalesnik that combine three set of variables into one, I try to do the same to combine two sets into one. I have problem to let the combine code to recognize a list that is to be passed to the variable. Here is the sample .ly code.
line 21 & 22 is the list define on line 6 &7. I cannot make Ez_noteheads-engraver to accept either line 6 or line line 7. Help is appreciated.