Final product below:
The idea came from paper garland, and I found the pattern from web.
Since the acrylic sheets are harder than paper, I tried the design with cardboard first.
I accidentally found out the shadow was beautiful. If I had a opaque acrylic sheet, I could carve some sentences between two edges, then it would have the sentences on the shadow when it was under appropriate light. But, I just recklessly bought a transparent clear sheet and didn't have time to buy another one for this assignment.
Then I started the first try on acrylic sheet (3mm) with a small model. I heated the joints and bent them one by one from outside to inside.
The problems are: It broke when the temperature was not high enough, and the angle of each joint was different. After I practiced, I got some experiences of this job.
After that, I laser cut another bigger one with more circles and with words carved at the bottom as decoration. I used wood sheets to secure the bending angle of every joint. It was still not that perfect because the wood left marks on the heated soft acrylic.
However, the outcome seems fine, and also has the beautiful shadow under light.
P.S. When I pictured it, I broke one of the edges in the middle. I think the acrylic sheet should be thicker than 3mm to make sure it's strong enough. And I can make a longer round headed wood piece to be the angle controller next time.