This is a fairly easy thing to design, once I clean up my files I will likely post everything in the free designs section. SVG files are available here: 8-bit Zelda Style Pixel Heart Necklace
My kids school has a tradition of “handmade” valentines. As we designed and made test cuts, it became obvious we needed a “jig” to help with fabrication.
There are cutouts for the chain and magnets which help to hold it together once fully assembled.