An idea from the earlier graduation season
The interviewer asked for 24 hours to complete a work.
Including product research and final results
This was an idea at that time.

The thermos cup is generally used in winter.
But the cold touch of its metal material cannot hold warm hands like an ordinary cup.

I hope that through the expansion and contraction of the cup lid, the cup lid and the cup can have the functions of hand warming and heat preservation.