Don't worry, nobody seems to have a consistent answer to this, or know what anyone else is talking about. I would say that I can visualize things, but that doesn't mean I literally hallucinate at will. Some people probably can but others will answer somewhere between 1 and 4 and when you ask them if they can hallucinate a red cartoon apple, hallucinate a white outline of an apple, that looks exactly the same as someone waving around a big white paper cutout of an apple, or shining a white flashlight with an apple outline taped to it, they say no???

if you think of what it would look like to graph y = x and you hold that in your head can you overlay onto that mental image another line of y = x/2?