How far back are we allowed to go. Decades ago I had a Original Commodore PET 2001. It could only display white text/characters on a black screen. Foolish me

How far back are we allowed to go. Decades ago I had a Original Commodore PET 2001. It could only display white text/characters on a black screen. Foolish me having read a Byte magazine describing how a black & white colour wheel could make you see colours see: https://archive.org/details/byte-magazine-1977-02/page/n45/mode/2up https://archive.org/details/byte-magazine-1977-02/page/n45/m... so I tried to get my PET colour to display colours using this method. Trying different timings, all the while staring at the screen. I did this all day looking at flashing lights all the time. Afterwards it turns out I could not see properly for hours.