What can you do with a mobile phone and a marble? ... This!
If I told you the image conveyed the book cover of a collection of short stories by one of my favourite writers you might just be able to work it out.
The author's name appears across the top while the collection title can be seen in the center.
Sorry, toy box marbles were never really designed as optical devices. You might just have to use your imagination.
Photo: Robert Rath, 'Marble Vision' 4s f/9 ISO100 100mm