DoReMi / Cup sounding melody of doremi

Sometimes whether the visually-impaired or not would spill a cup with water. I have poured water in a dark living room. I set my thumb inside cup to measure the height of water filled into.
Then the DoReMi cup suddenly occured to me.
DoReMi cup makes pouring water not tedious or difficult for both them. It sounds do, re, mi~ do when it is being filled with water. So you can know how much water has been filled into the cup even though not looking at.

The visually-impaired should practice to pour water countless times. They have burned their hands due to overflow hot water. DoReMi cup also makes them pour easy and interesting.