Some colors to avoid include orange, red & green, and blue and green (Lambert, 2018; Penn State, n.d.). Text color that is too similar to the background color will be hard to read (Kalbag, 2017, p. 75 ...

Or, if you were only able to see the green light, you'd know you're looking at the plane's right side.If both lights were the same color, you wouldn't be able to tell which side of the plane you ...