No window over sink. Maybe an old window, painted panes - mount over kitchen sink. build a light box and place string lights around hidden inner edge to illuminate? Could also be done with old strained glass window.
Vintage flower window: I use stained glass scraps, and cut them with my glass cutter. Then I lay the pieces out on the window I then glue them down with silicone and wait 24 hours to dry. I use sanded grout, black is my grout color of choice,