What makes the designs you see so appealing?

It depends on what type of third separates the three notes.for example: if you have two mayor thirds is an "aumented chord"if you have two minor thirds is an "diminued chord"if you have one mayor first and then one minor is a "mayor chord"and inverted is a "minor chord"

Answernon-religious themes became more popular, and people also wanted to show off their wealth because painting was a sign of this at the time;

Ithink the answer is true.