Only clue the party has was a letter sent by the inventor of this puzzle box:
My dear friends,
I have started working on your order of this gambling machine.
However, I have to admit I have lost interest midway throught the project.
But, I think I have turned the project around,
and made it into something both of us can find interesting.
Hope the patrons of the bar do not hate me for this.
But hey, you can open the machine anytime you want.
Let me know what you think.
Yours truly,
L
I will maybe reveal the solution at a later post.