Coin and Ring

You know, from the video games.

Anyway, I drew the coin, and was quite impressed by it. But the more I looked at it, the more upset I got with the shading things... Ugh. I guess it works better than nothing. And I have no idea how it works like that, or the reasoning behind it. Only that it worked and stuff. Which is probably bad, but oh well. The nub in the middle looks okay though. But adding a shadow to it works wonders.

The ring looks quite good. Although I'm not sure how easy it is to make out the shading. Do you even have to? I don't know. The curve of it looks pretty good though, which is surprising to me.