[Stefan] from CNC Kitchen explored an unusual approach to a multi-material print by making custom PLA filament with a TPU core to make it super-tough. TPU is a flexible filament whereas PLA is hard almost to the point of being brittle. The combo results in a filament with some unusual properties, inviting some thoughts about what else is possible.
This is a companion discussion topic for the original entry at https://hackaday.com/2024/05/04/3d-printing-in-custom-pla-with-a-tpu-core/