"Do you have a source of colorful light that you can put under your oil and water pan? A tablet computer and a search for "colorful backgrounds" works well."
This has been such a great challenge! I like Gustav Klimt and chose some of his colourful pictures as my "background". Though, I must say, that it's more than a background.
Comments and suggestions are much appreciated!
Here are my get pushed-challenges
Update 05/2019: Year 3 begins! I'm living in Bremerhaven near the North Sea since October...
But without the teasing I like the refractions in the oil drops!