Over the years I have bought many books, large and small, with hard covers and blank pages. These I use partly as commonplace books, writing in longhand passages from things I am reading, but also to record when an insight, a thought, rises to the surface. I now have a large collection of these books, full of rich quotations and insights.
It is the same when we meditate. We make ourselves a tabula rasa, an empty canvas, onto which, either during the meditation or in the space afterwards, we find certain insights or images imprinting themselves on the blank page of our consciousness. But first we have to learn how to be a blank page!