There's room for one more llama.
Drop colorful llama heads and bring matching ones together. Two of the same become a bigger one. The llamas roll and shift around, though – that nice gap you spotted might be gone by your next drop.
Sometimes the matching llama is right next to yours. Sometimes another one is in the way. Merge several pairs in quick succession to get a combo and extra points.
The stack keeps growing until you run out of room. Your best score stays saved for the next round.
Stack llamas, merge matching ones and make room for the next.