Use "oculus" in a sentence

1. There’s a spell on the oculus above that diverts rain to the cisterns

2. There were no windows but an oculus allowed light to enter and spread out, illuminating the tables and workstations of the officers and generals who strategized

3. Murphy opened his wings, grabbed told hold of Corwin’s belt and flew out of the oculus without breaking a ward; the magic simply parted around him as he followed the bird into the sky