To imply greater depth, the sculptor who created the relief carvings on the outside of the ara pacis augustae carved the figures in the more deeply than those that are in the background, in order to make them stand out more.

To imply greater depth, the sculptor who created the relief carvings on the outside of the Ara Pacis Augustae carved the figures in the FOREGROUND more deeply than those that are in the background, in order to make them stand out more.

Explanation:

The Ara Pacis Augustae is an altar dedicated to Roman Emperor Augustus (the name in Latin literally means Altar of Augustan Peace).

The exterior decoration of the altar is mainly composed by relief cravings. The sculpture wanted to create an effect of depth, so this is why the figures in the foreground are carved more deeply (high relief) than those in the background (low relief).  

i'm not sure i completely understand your question, but i will do my best.

i think the answer you are looking for is sequence. (see below)

a repeated melodic fragment would be best defined as repetition, while repeated chords (different or the same) could be a chord progression. however, you then mentioned the chord and melodic fragment beginning on higher or lower pitches, in that case, the answer could be best defined as a sequence. the definition of a sequence is as follows: "the restatement of a motif or longer melodic (or harmonic) passage at a higher or lower pitch in the same voice."

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