There are many ways really, and some have been explained above.
Now if you really believe that your design is groundbreaking, and you
are able to invest on it for longterm
, then I suggest to first protect it
(patent, copyright, trademark etc), and then
show it to others.
The investment does not have to be your money. It could be people that
you know for years and (preferably) that you trust. But you need to
convince them that your puzzle/toy will be successful. If you do not
want to manufacture yourself, there are more than one companies
who could be willing to get a license.
Always make sure you sign proper agreements without loopholes.
I am not a lawyer (far from it actually), but I have been told those
But as I said, you need financial aid, patience, the correct people,
and... patience!!! (yes, there is a reason I said "patience" twice)