that is really good shading

wow

ok you can ignore this comment if you want i just wanted to give a tip-- just like one thing you can improve, I think, is to make the darks darker and the lights lighter. Real life has very dark darks, especially on light colors! Another thing you could do to make it more realistic is to shift the colors a bit. Like, on the teal one the darks get more blue and the lights get more green once again, you don't have to listen to me, but it'll help you I think :)