As I was working on on the "Let's Draw Inside Out" fan art January session of Joy, I realized that I really loved that Pixar carried over the particle nature of the characters into the eyes as well. We all know that Pixar has that signature eye look (and the iris of the eye usually has straight lines that make up the iris)...but I love that they continued the particulate look into there as well.
Here's an example comparing Merida and Mike Wazowski's eye(s) to Joy's so you can see the straight lines compared to the particulate lines in the iris. It's nothing earth-shattering, but I thought it was really cool to see how they carried the particles into the eyes for these characters - which, to my knowledge, they've never changed the look of the eyes on any previous characters...have they?
Oh, and if you haven't joined in and started drawing fan art of Inside Out yet, check it out and submit your entry too!