Hearing Wring That Neck again reminded me of a story connected to it. Around 1969 Deep Purple were in the US and met with a band called It’s A Beautiful Day. As legend will have it. Jon Lord for a short while dated Pattie Santos, on of the singers in this American band. It’s A Beautiful Day released their self-titled debut album in 1969, and the intro to one of the songs on it sounds suspiciously like the intro to one of the biggest songs in classic rock.
It’s A Beautiful Day - Bombay Calling (1969)
It’s Beutiful Day then borrowed the theme from a Deep Puple song for the opening track on their second LP Marrying Maiden, released the year after. Guess which song 
It’s A Beautiful Day - Don And Dewey (1970)
There were no lawsuits and no hard feelings. Both bands acknowleded that they had borrowed from each other. Perhaps the mindset of musicians were a little different back then. The four songs stand out well on their own anyway.