Parcel Post 3D Wooden Packing Puzzle – The Ultimate Brain Teaser for Expert Puzzlers & Collectors

Product details：

Packaging: Storage Bag
Marterial: wood
Difficulty Level: very high
The quantity of wooden blocks: 18PCS
Warning: small parts, not for children under 3 years

The mission of the puzzle:

Put all the 18PCS wood pieces into the three layers wooden board, very challenging!

What Is the Parcel Post Puzzle?

The Parcel Post is a classic and notoriously difficult 3D packing puzzle. It consists of 18 rectangular wooden blocks (cuboids) that must be packed perfectly into a rectangular box. The box measures 6 x 18 x 28 units in internal dimensions, and all pieces together have a total volume of 3024 cubic units – meaning the box must be filled completely with no empty spaces .

The 18 pieces are mostly of unique dimensions, though three pairs share the same size. Their dimensions (each being 2 units thick) are as follows :

The Challenge – Why It's So Hard

At first glance, the puzzle seems straightforward: all pieces are flat (2 units thick), so you might naturally try to pack them in three flat layers inside the box. However, this is a trap.

There is no solution where all pieces lie flat . To solve the puzzle, some pieces must be placed vertically (standing on their edges), creating an extra layer of complexity as you must also figure out which layer each vertical piece belongs to. Some sources even note the solution can include empty spaces, adding to the complexity .

Due to the large number of pieces and the deceptive simplicity of their shapes, the Parcel Post is considered an extremely difficult puzzle. One collector rated it a level 8 out of 10, but later admitted, based on experience, that it's truly a level 10 challenge .