The Extra T!

A devilish puzzle
Not 6T but 15T!

Child’s shape-sorting box or a diabolical puzzle for seasoned adults?

At first glance, this puzzle looks like a simple children's toy. A box and 15 T-shaped pieces… What could be easier? But don’t be fooled! This fiendish puzzle will put your logic and patience to the test.

Your mission: Fit all 15 T’s into the box. Sounds simple, right? And yet, very few manage to find the solution. Will you take on the challenge?

When you try, fitting 14 is already tricky, but the last T just never seems to fit! 😉

And yet, I assure you—it’s possible! (see the last picture …)
There is only one unique solution, and exactly 5 empty spaces must remain.

Will you manage to fit the extra T?
If not, you can always place it in the hole on the lid 😉
It can also be used as a shape-sorting box for kids.

Maybe you'll be among the few who conquer this puzzle…

Did you succeed?

Let us know—and let others struggle with it too!

🧠 Happy puzzling!

Notes

🔹 The T’s can pass through the holes in the sides and the lid, but that won’t solve the puzzle!

🔹 The T’s are made of 2cm cubes, and both the pieces and the box have nicely rounded edges for a smooth and pleasant handling experience.

🔹 I’ve added a medium-sized 4x4x4 box, where 12 T’s can fit.
This is a much easier challenge (you can test it with the larger box by forbidding yourself from using the top layer).

🔹 There’s also a small 3x3x4 box with a lid for the classic 6T puzzle.
Reminder: In that one, you must fit 6 T’s inside the small box—but only through the lid’s hole.

🔹 You can print 4 T’s in 4 different colors on a plate using an AMS.

🔹 Start by printing 6 T’s and the smallest box to begin playing while waiting for the other pieces to finish printing.

I don’t know if this puzzle already exists—I discovered it while exploring similar challenges after printing a 6T box.
If you’ve seen it before, I’d love to know!

I’m currently working on more puzzles with polycubes—stay tuned!