What are the characteristics of post-impressionism?

Post-Impressionists extended Impressionism while rejecting its limitations: they continued using vivid colours, often thick application of paint, and real-lifesubject matter, but were more inclined to emphasize geometric forms, distort form for expressive effect, and use unnatural or arbitrary colour.

Vivid colours, Thick paint layering, and real-life subject matter.

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"