That's indirectly reminded me of something. Synathesia...synthesthesia...bah, I'll have to ask the duck...synaesthesia. Input to one sense being copied over and interpreted into another sense. Not quite what you describe, but similar. Some people have it all the time - they see sounds, smell colours or whatever. It sounds strange and confusing, but it's not because you're just getting interpretations of sensory input like you always do. Sensory input that's not actually there, but it's presented to your consciousness in the normal way so it's normal and thus not strange and confusing. If a certain sound is a certain shade of green, well, that's how it is. I've had it when taking LSD...which brings me back to the topic of this thread because I could then visualise imaginary things and "see" them in the way that apparently almost everyone can do normally.