This was a new concept few years back, and was interesting to see how the gift shops took to customizing this for friends and families. A recent variation of the same seemed to capture my interest!
Heat changing cups concept
When something is hot, the cup on the outside changes appearance giving a visual cue to the one drinking it. Aimed at not burning ourselves drinking hot fluids, this was a welcome change. Personalizing it, took it to a different level of creativity!
Variations only used to be on the outside of the cup for the visual cues.
differentiating cold liquids – an artistic twist
Now, how would be if the insides of the cup were changing colors or patterns. Japanese cherry blossom designs seem to be perfectly depicted in these designs. The colorless liquids (Mostly variations of tea), hot or cold can be differentiated through the evolving patterns! So beautiful and artistic!
See the flowers bloom when the liquid is poured in the cups!
Differentiating hot and cold
The same Sakura cup designs differentiate the hot liquids from the cold, by making different colored flowers bloom to reflect the temperatures!

Lovely design and creativity!