First you will need the cheat gnome as follows:
Cheat gnome: b,z,up,down,b (the gnome will appear in different places depending which
island you are on)
Then you will have to follow this series of buttons as follows: all plan: +,+,-,-,z
If that code dosen't work try as follows: all plans: quickly press: plus, minus, minus, z
Also you need a certain level of mechanical and creativity in order to build them.
There is also a cheat for this on the cheat gnome as follows: add 1 to a skill:
z,up,right,z,right
If that cheat does not work try as follows: add one to skill: quickly press : 2, up,
right, z, right
(caution: the skills cheat will only allow you to add one point to the skill you chose
though you can do it repeatedly untill you have reached you goal)