Not only were the massive square of stone that formed the wall played on by different lights as the play proceeded ; .
The sky beyond the jagged cleft changed gradually from the intense blue of full day to the softer colors of dusk , thus giving differentiation .
Not only were the massive square of stone that formed the wall played on by different lights as the play proceeded ; but the sky beyond the jagged cleft changed gradually from the intense blue of full day to the softer colors of dusk , thus giving differentiation .