While looking for ideas for a present for an 8yr old, I stumbled across the design for the Finger Spring. I printed one and loved it. However, I wanted it to be a game of some sort, for him and his two younger brothers to be able to play. So, I started looking for a cool cup that they could try to shoot the spring into. Enter the Folding Cup. I did a quick look in Cura and it looked like a good fit. The fit is so good that the cups base will hold 6 of the Finger Springs perfectly in it. The enclosure for the Folding Cup keeps everything together.

I printed everything at 100% of the original size in the STL files, which are attached. The only thing that I did was to print the top & bottom of the enclosure on one plate, the inner-walls and cup base on another plate, then 2 springs per plate (2 per color), but you can easily print all 6 on one plate. When printing the enclosure, flip the top (Tapa_v2.STL) so that it prints upside-down. Zero modifications were made to the original STL files.

I used Sunlu Transparent PLA, at 205/60, with 15% infill, zero supports, on my Klipper'd Ender 3v2.

Edit - Once the outer container was printed, I had to do some post-processing work to it, as follows:
The bottom of the container (has the large hole), the bottom of the cup needs to be filed around the bottom edge until it has a snug fit in the large hole. It should be flush across the bottom. Once a good fit is achieved, permanently attach them together with super glue. Allow the outside to thoroughly dry, then pull the cup pieces up securely, then apply glue around the inside of the large hole where the cup bottom meet. Be sure to have all of the cup pieces added before you glue the container and cup bottom together. Don't ask how I know.

Next, the locking "ridge" on the top of the container needs to be filed down until it's somewhat easy to pop apart. I used a precision file set from Walmart ($4.98), mainly with the flat file, but used the rounded one to finish it.