Refurbished Flip Flops

I had these really gross white flip flops and unfortunatley they were the only shoes I could find for school one day... So I was sitting in Spanish and i looked down and the design came to me. So I started doodling on my flip flops.... much to my teacher's annoyance:D And this is what I came up with.

The Swirls are nail polish and the black is acrylic paint. I drew the patterns in pen then outlined them in a sharpie.

I sealed them with mod podge but I have to polyerthane them or something to make them waterproof.