(yes i know the title may be a mouthful...)
So sometimes when i get tired I hallucinate the smell of rust, this is a common occurence for me... also when i listen to music, i often get Synaesthesia involving my sense of smell... one song i got a very strong smell of ladies purfume... while another flowers... yet another motor oil... I can also "See sound" like for instance a loud bang also can have a flash to it even if there was no actual flash of light, while the vibration of say a ballast could also radiate a sortof steady "glow" sometimes. I mostly only "see sound" in black and white. not really any colors i've experienced so far...
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For info on Synaesthesia)