My awesome schoolfellow Tom Arthur has made a flip clock (has 5 digits in total), and he led me a lot of useful resources. Really appreciate it. You can check his website here. Also, other resources include BeachLab maker space in europe, and Tom Lynch's work.
Initially, I was thinking they look really lovely when its flipping, as what I expected. However, meanwhile, the question that how could I improve that as the need of my project. Even though, they will show date and time similarly, for REMEMORY, since it should be an emotion trigger, the acrylic box does not fit to that purpose anymore for sure. I started sketching and trying to improve the form of it.
Here is the final illustrations of the design. I leave the bottom part open to highlight the movement of the flipping board. I will build the inner structure (metal) first to link 6 digits together tightly and reliably; then CNC a wooden cover and put it on top of the structure.
In the first place, I was thinking fixing stepper motor to wooden cover, however, in terms of the convenience of product maintenance, keeping all parts together on inner structure would be more reasonable.