Artistic depth has two possible extremes. One extreme tries to express itself with an increasingly diverse set of stylistic ideas, choosing to portray emotions with whatever musical idea suits them best. The other extreme of artistic depth is the exploration of a single idea from as many angles as possible. Robert Schumann once hammered the same a note on his piano until he went mad, looking for possibly the perfect expression of that one note. Steve Reich explored the shifting of rhythms, creating rhythmic polymeters as dense as they were fascinating. Cephalotripsy slam. And they do it a lot.