Rush began life as a power trio in the Led Zeppelin/heavy rock mode.
Over the years the band refined their musical vision as they gained both instrumental and conceptual facility.
1978's HEMISPHERES marks their transition from heavy riff-mongers to full blown art-rockers.
Lee, Lifeson and Peart employ a number of tricks from the prog-rock bag here; (very) extended songs, multi-part suites, long instrumental passages, rapidly shifting tempos and time signatures, complicated unison riffs and synthesizer orchestrations.
It's to Rush's credit that these elements enhance their sound instead of obscuring it.
In fact, "La Villa Strangiato" would become one of the band's best-loved '70s efforts and a long-standing concert favorite.