anyone can tell me some ruby gems that has a model of great oop design structure so that i want to study in order to improve my design oop skills

I already stuudied and read about oop design, solid and some design patterns but enough theory i want to see it in real practice.

my really goal here is get better compreension in creating classes and structure following good patterns reading some code examples

I have a great underestant of ruby language, and rspec/minitest/gem so that i can study other's code.

so can anyone tell me some ruby gems that has great oop design structure that can be served as example of a good design and that can be studied in order to improve my oop design skills