[Reflect on the process of making this project. What did you learn? What would you do differently?]

I should have checked the minimum resolution of the printer before beginning my project. I learned understand tools that I would use is very important. Also, I missed the procedure testing materials like magnet and keys. I was misunderstanding the characters of the materials, and I found it after the first prototype. If I had tested it before printing the holder, I could have found it. And the failure of the magnet led me to alternating the mechanism of the holding way from magnetic force to physical barrier via a bar. On the other hand, the size of the holder was well determined because I measured and reflected the dimensions of my keys.