I have heard the Mental Block uses the Skewb mechanism. Does it have any special modifications other than the shape of the exterior? Also, I am having trouble visualizing how it could be a skewb. Which pieces are attached to the 4-armed spider? Thanx.

All skewb puzzles, whether spheres, cubes, or octahedrons, have 6 "square" pieces and 8 "triangular" pieces. Imagine a puzzle in which all of these pieces are flat. In that case, you have a cube-octahedron. (The Rainbow Cube is another cube-octahedron.)

Now look at a picture of the Mental Block. The centers are square pieces, and the corners are built up from squares. The edges are built up from the triangles. The triangles attached to the spider are left-right edges on the front face and the up-down edges on the back.

As for any special techniques for actually building them, somebody else might be able to help. It looks very difficult to me.

I am planning to build a Mental block.

The kernel will be a Skewb keychain, You would also need two more Skewb just the squares for the surface. This would make an Mental block, just a bit bigger as a 3x3x2.

The Big corner pieces you should fill-up with foam or waist plastic and than apply Milliput. If you do it like this, the puzzle will not be to heavy. Tip for Stickers, the two flat sides you could reuse the Swekb stickers.

The material cost would be:

3 x Keychain skewb $15
1 x Milliput $10
stickers $ 5
So in total about $20

I will make a prototype,
Ton

Thanks for the info!
I'll have to make one once I learn how.

Just one question: where can I find Milliput?

As soon as my supplies arrive (still havent shipped, and they had the nerve to change the status of payment on my credit card from pending to completed)
i will post pics of each individual piece. As for technique of building, i will decide whether i will release that information, it actually is simple.

Now I get it. Don't know why I didn't see that before. I've never custom-made any puzzles but would like to get into the hobby.

Try your local Plastic Model building shop, or shops that sell model trains, electric wired model cars or some hardware stores.

P.S. For little cracks you normally use Putty.

Milliput is also used for:

Reef Construction - fish shops
Rapair Radiators - car shops
Ceramics repair

Else try

http://www.milliput.com
Emai: info@milliput.demon.co.uk

I dont reccomend the use of milliput for this type of extension, instead use something like wayne does.
I should have my mental block complete by monday, supplies arrived today so as soon as i finish a few essays i will get to work.