Okay, I'll take a Wild Guess... The Metal Plate formed a Magnetic Attraction on top of the Liquid, which caused the Tiny Particles floating on top of the Liquid to form in the image of the outer and inner lines and curbs of the Metal Plate... It all seems impossible, but it did became a Mirror Like image Floating on top of the Liquid... Actually, I just figured it out... The bubbles were raising to the top of the Liquid from the Plate that was beneath the Surface... That sure put my Wild Guess all to shame...