The use of different musical styles or techniques in a composition is known as

The answer is polystylism. Polystylism is the use of multiple styles or techniques in not only in music or composition also in literature, art, film, or, especially, music, and is a postmodern characteristic.  The mixture of two traditional chords sounding together is known as a polychord. 

well seeing i am an artist and i actually did a self portrait; i will describe how i painted it.   i used acrylic on a stretch canvas about 4 feet wide by 6 feet tall. i painted myself smiling in a soft pink long dress, white tile floor sitting on a white couch with a table behind and a vase of gorgeous flowers.   i also had a round white hat with a soft pink ribbon through it laying on the floor and on the table behind me was a lit candle. i kept it simple but soft and romantic.