Radiohead90

One thing I always noticed basically every early Progressive Rock artist from Yes to King Crimson cite the Beatles as a influence.

A Day in the Life", "I am the Walrus", "Within You, Without You", "Strawberry Fields"... not really blues tunes, are they (Doh?). They were able to draw from diverse sources, like Indian classical music (Within You uses a raga-like form that contains both major and minor thirds in different octaves, kind of a combination of mixolydian and dorian modalities). Lennon used forms similar to Tibetan chants. They were versed in the same types of cadential cycles that had evolved from Dixieland and Tin Pan Alley, the pop music of the previous era (and also a primary underpinning for jazz). And they invented many new forms in between. IOW, while most other bands of that era were still working within simple I-IV-vi-V frameworks, the Beatles had assimilated musical forms, languages and rhythms from around the world. They built their own unique musical sounds, and wrote some of the most widely recorded music in history.

Also I think they were one of the first rock groups to experiment in mixed time signatgures I think "She Said Said She" at one point is in 8/5. Their psychedelic style of Indian Instrumentation, tape loops, and electronica on "Tomorrow Never Knows" and "Strawberry Fields Forever" sounds like nothing else recorded at the time. I consider "A Day in the Life" a true progressive rock song.