I saw a bit different exploding box and thought, well, I'll try something.
No decorations or anything, because I just wanted to publish the freebie.
1. Here's the box.
2. Another pic of the box.
3. This is very very very easy to make, and I drew a sketch.
You need 21 cm x 21 cm square.
You need 13.5 cm x 13.5 cm square.
Hope you like it. :)