Complex sentence: Interestingly, much of this artwork was carved on the backs of the stones; a type of megalithic art known as hidden art. This suggests all manner of theories as regards the function of megalithic art within the Neolithic community who built the monuments in the Boyne valley.
Split into simpler sentences: Interestingly, much of this artwork was carved on the backs of the stones. This type of megalithic art is known as hidden art. This suggests all manner of theories as regards the function of megalithic art within the Neolithic community who built the monuments in the Boyne valley.