- Create unique, customizable messages or designs on metal jewelry with specific areas microtextured to create regions of superhydrophobicity and superhydrophilicity. For example, a wedding band would look plain when dry, but when you wash your hands the message, "I do" or "I love you" appears in water droplets. The message would go away as the surface dries. I think Hoowaki could handle this.
- Tattoos that use biodegradeable ink so that they fade and disappear after 5-10 years. This would be a good alternative for people that want a genuine tattoo, but don't want to look like a punk when they are 70. Maybe this would work if you used food coloring or inks derived from natural products. It would also be neat if you used glow-in-the-dark ink or UV sensitive ink.
