Did earlier thoughts inspire Grothendieck ?

When I first met Alexander Grothendieck more than fifty years ago I was not only deeply impressed by his creativity, his knowledge and many other aspects of his mathematics, but I also wondered where all his amazing ideas and structures originated from. It seemed to me then as if new abstract theories just emerged in his mind, and then he started to ponder them and simply build them up in their most pure and general form without any recourse to examples or earlier ideas in that particular field. Upon reading his work, I saw my impression confirmed by the direct and awe inspiring precision in which his revolutionary structures evolved. Where does inspiration come from ? We can ask this question in general. The question has fascinated me for many years, and it is particularly intriguing in connection with the mathematics of Alexander Grothendieck.