Credit to artist st.Krojak for his 3D-Model of the millenium eye: https://sketchfab.com/3d-models/free-millenium-eye-print-ready-yugioh-8f9df2111412497e819de029717ea59d

I halved the eye for easier printing without supports. I hollowed both halves so that you could put metal/sugar/whatever inside to give it a heavier feel before glueing both parts together.