An interactive, multi-piece toy grenade inspired by the classic MK2 design, engineered to get kids active outdoors and practice their throwing skills!

How it works:
1. Assemble the 4 shell pieces around the core using a standard rubber band.
2. Secure the safety lever (spoon) and insert the cotter pin (safety pin).
3. All parts (including the lever and shell pieces) are connected to the main core by a thin string, ensuring that nothing gets lost after the "explosion" and cleanup takes seconds!
4. The Action: Pull the pin while holding the lever – nothing happens yet. Toss the grenade! Once released, the rubber-band-driven mechanism triggers in mid-air, causing the shell to safely burst into 4 independent pieces upon impact.

Hardware & Assembly needed:
- 1x Standard rubber band (for the mechanism trigger).
- 1x Cotter pin / Safety pin (or a piece of stiff wire to secure the lever).
- Thin string / Cord (optional, to keep all parts together after impact).
- uperglue (Cyanoacrylate): Please note that one of the mechanism parts is specifically designed to be glued in place during assembly to ensure the structural integrity of the internal core.

Printing & Material Note:
I designed and successfully printed this model using impact-resistant resin to withstand rough outdoor drops. However, it can absolutely be printed in FDM! 
For FDM printers, I highly recommend using durable materials like PETG or ABS/ASA (or at least tough PLA with increased wall count/infill) so the shell pieces can survive repeated impacts on the grass.
 

Bring some action to your backyard! If you like the design, please leave a review and share your prints!