The best way I've ever had a friend (who was red-green colourblind) describe his colourblindness to me was using a picture with coloured pencils (see the link). One set were normally coloured; the other set were what people with red-green colour blindness see, so he couldn't tell the difference. Not sure if it matches what Trevor has, but it's a fun comparison for anyone who's curious 😊
https://i1.wp.com/www.techwelkin.com/wp-content/uploads/2014/08/red-green-color-blindness-techwelkin…