Good, good!! Stay with it, stay relaxed, and keep building on these experiences!

Spend some time reflecting on what this experience felt like. Part of what you're training yourself to do is recognize what dreaming is like. Now you've had the experience of having your "waking mind" experience a brief taste of the dream world. You're growing the mnemonic skills that you'll need to kick yourself into lucidity in your DILDs.

Your use of the term "caustics" makes me wonder whether you have experience working in computer graphics or some other area of art. Experienced artists or graphics programmers tend to use that term a lot but I hardly hear it anywhere else. Anyway, great imagery there.

Great stuff. You'll experience many of these small victories along the way, and each of them will always be special to you. Congratulations!