Which Gregorian chant was used in Berlioz's Symphonie fantastique?

In the Rubin vase illustration, the black shape can be seen alternately as a foreground object resembling a vase or as a background space between two white profiled faces. What is this relationship called?

a) figure-ground reversal b) atmospheric perspective c) scientific perspective d) linear perspective

True or false: A photograph is only successful if all viewers walk away from it with the same impressions of it.

a. True b. False