As a kid, before I even knew I was colorblind, I remember experiencing this with my Nintendo DS’ battery LED indicator. I believe it would show green-yellow-red

As a kid, before I even knew I was colorblind, I remember experiencing this with my Nintendo DS’ battery LED indicator. I believe it would show green-yellow-red, but I could never tell the difference just looking at normally. I would instead bring it right up to my eye, thereby filling up my entire field of view and I could suddenly tell what color it was. This article finally gave me insight as to why.