Index: cfg.py
==================================================================
--- cfg.py
+++ cfg.py
@@ -108,22 +108,22 @@
                 "lead_instr": {  # Instrument 'melody'
                     "score_line": "i1 %(time)f %(duration)f 7000 %(octave)d.%(note)s %(octave)d.%(note)s 0 6",
                     "octave": 8,
                     "duration": 30,
                     "grammars": {  # Notes for this instrument to use in this piece
-                        "u": ["D/4 D/4 D/4 D/4"],
-                        "v": ["C/4 C/4 C/4 C/4"],
+                        "u": ["D/4 D/4 D/4 D/4 (u)"],
+                        "v": ["C/4 C/4 C/4 C/4 (v)"],
                     },
                 },
                 "follow_instr": {  # Instrument 'melody'
                     "score_line": "i2 %(time)f %(duration)f 7000 %(octave)d.%(note)s 1",
                     "sync": "lead_instr",
                     "octave": 8,
                     "duration": 30,
                     "grammars": {  # Notes for this instrument to use in this piece
-                        "u": ["D/4 D/4 D/4 D/4"],
-                        "v": ["C/4 C/4 C/4 C/4"],
+                        "u": ["D/4 D/4 D/4 D/4 (u)"],
+                        "v": ["C/4 C/4 C/4 C/4 (v)"],
                     },
                 },
             },
         },
     }
@@ -187,27 +187,27 @@
             if score_index_to_replace is None:
                 raise ValueError("No more nodes to fill in")
 
             time_remaining = max_time - score_len(score)
             new_phrase, syncs = choose_phrase(instr, syncs, score_len(score), time_remaining)
-            score = score[:node_index-1] + new_phrase + score[node_index+1:]
+            score = score[:score_index_to_replace-1] + new_phrase + score[score_index_to_replace+1:]
 
     except ValueError:
         return (score, syncs)
 
 
 def choose_phrase(instr, syncs, current_time, time_remaining):
     '''Filters grammars for ones that match the sync option, and phrases that fit the time remaining in the score'''
     time_filtered_grammars = {}
     for grammar in instr["grammars"]:
-        time_filtered_grammars[grammar] = get_phrases_that_fit(instr["grammars"][grammar], time_remaining)
+         fitting_phrases = get_phrases_that_fit(instr["grammars"][grammar], time_remaining)
+         if len(fitting_phrases) > 0:
+            time_filtered_grammars[grammar] = fitting_phrases
     if len(time_filtered_grammars.keys()) == 0:
         raise ValueError("No available grammars that will fit in the score")
 
     grammar = None
-#    if instr["name"] == "follow_instr":
-#        ipdb.set_trace()
     if instr["sync"] is not None:
         guiding_instr = instr["sync"]
         sync_node = get_sync_node_at_time(syncs[guiding_instr], current_time)
         if sync_node in time_filtered_grammars.keys():
             grammar = sync_node