who started the trend of turning the piano sideways in concerts to allow the audience to better see the hands of the pianist while also hearing the intricate sounds produced by the instrument?

Franz Liszt

Explanation:

Franz Liszt a Hungarian composer who was prevelant in the Romantic Era for his ideas such as moving the piano sideways, as well as making his most famous song, "Piano Sonata in B Minor (1853)."

Turned piano sideways so audience could see his hands and profile. Developed new style of program music: The Symphonic Poem/Tone Poem. Created by Liszt. One-movement orchestral composition with contrasting sections to develop a poetic idea, suggest a scene, or create a mood.

Explanation:

thanks

answer; gordon allport; good luck