Yes, it can be gradual also! The other day, someone was telling me, “Gurudev, suddenly, I realized that I am happy all the time now, which I never was before!” A sudden realization comes that gradually you have become more and more happy. One day you find yourself saying, “I am so happy, so centered; nothing can shake me, nothing can take my smile away!” And then you are there!
Sometimes, there is a flash of lightning, and suddenly you see things, and then it disappears. Sometimes it is like when the sun rises, dawn comes first, then gradually darkness disappears, and day dawns very gradually, and that stays! So both phenomena are there. For some, it can come as an electrical transformation, for others it could be a gradual change. Sometimes you don’t even notice it, but one day, you say, “Wow! Aho!” Just like what is said in Ashtavakra, “Aho! Yes, I got it!”