I pondered about this before, and the idea amused me because it was unusual. Unusual in the so-called serious models, I think.
Jeweling on periscopes.
Over a black base I painted some greenish blue, then mixed some bright blue in, and finally used the blue, to paint an ever-smaller L shape into the 'scopes. Plus the whiteish anime dots into opposing corners.
Looks fun to me! For a more realistic look I would've done greens, but this stood out better. For funsies

















