The two Donatello's characteristic formal contributions are encountered in the work for Baptistery of Siena. He demonstated it through organizing the relief by a rigorous application of the rules of perspective. Even though it was created at a shallow deptht, this technique makes each figure of a scene emerge clearly and very logically. This technique is determined as a flattened relief.
I believe the answer is Rubato, when composers slightly slow down or speed up the tempo of the music
