The Trapped Cross – A Puzzle with Invisible Tenons

A specific print order is required. Please read the instructions below.

📝 Description:

At first glance, it’s just a stylish 3D cross inside a spiky star-shaped frame. You notice a tiny bit of wiggle between the two parts, and you hear something rattling inside…

But in reality, **nothing comes apart**.

**The Trapped Cross** is based on a wooden puzzle I’ve owned for a long time. I recreated it to practice modeling — and gave it a sneaky little twist in the process 😏

🎯 Why this puzzle messes with people:

• The **visible wiggle** between parts makes people believe there’s a trick.
• The **grooves** on the cross suggest something mechanical or unlockable.
• The **outer star** screams “twist me or pull me” — but that won’t help either.
• The truth? **4 internal dowels** inserted during printing keep everything completely locked.

➡️ The only real solution… relies on **a bit of physics.**

🗣️ What to tell people trying it:

🔐 “The goal is to **free the cross**.”
🚫 “Don’t force anything.”
And then — let the frustration begin 😇

🖨️ How to print it (important!):

🧩 **Plate 1 (must be printed first):**

• **4 internal dowels**
• **2 temporary spacer pieces** used during the assembly
  • Prevent dowels from sliding out while printing
  • Can be kept for future reprints
• ✅ **Infill: 100%** – the dowels need to be heavy

🧩 **Plate 2 (main cross + star frame):**

• Includes an **automatic pause at layer 151 / 30.2 mm**
  ⚠️ Adjust this if you scale the model
• At the pause:
  • Insert the **4 dowels** and the **2 spacers**
  • Resume printing to seal everything inside

• ✅ **Infill: 8%**
• ✅ Enable the option: **“avoid crossing perimeters”** (important!)

✅ **Bambu Lab users:**

The provided **Bambu slicing profile already includes the pause and correct settings.**
👉 Just make sure you **do what’s needed at the pause**: insert the parts and resume the job.

**🧩 Assembly:**

🔹 Once all parts are printed, start with **one of the cross pieces**.
✋ Gently spread the **tenons** with your fingers.
↘️ Slide the piece **diagonally** through the center of the star.
🔹 Then take **the second piece**, spread the tenons again, and **carefully slide it into position**, aligned with the first.
🔄 Once both parts are in place, **gently rotate the cross in all directions** to let the tenons fully engage.
🔒 And that’s it: **the puzzle is locked.**

✨ Creator's Notes:

I wanted to model a puzzle that **seems solvable**, but really isn’t — unless you know what to look for.
Yes, if you're very careful and patient, you might eventually loosen it…
But the true solution comes from **an unexpected kind of movement**. Makers will get it. Testers won’t. And that’s what makes it fun 😉

🚀 Enjoyed it? Help out!

👍 Give it a like
📸 Share your printed version
💬 Drop a comment (I read them all!)
🚀 **Boost it** to spread the trap
And above all: **don’t spoil it for others 😄**

Casse Tête Anonymous63 | Collection - MakerWorld : Download free 3D models