Did anyone make this before?

It has been done before. Saw pictures on the web years ago. Some Asian builders modded standard 3x3x3 cubes with chains. They hammered nails into the corners or edges of the cube, attached chains, and adjusted the length of the chain just so that the two corners could move freely around the cube but were restricted to always being adjacent to each other. On one cube, there were two sets of such corners. Endless variety of possibilities with chains, corners to corners, edges to edges, multiple chains on a cube might get kinked together etc. The cubes had a very demonic look to them.

Here's an idea to get the ball rolling: You could try it with bungees and have many pairs of pieces mated together. When you scramble it, would probably create a complex twisted jungle of entanglements. Think Brainstring + 3x3x3. Traditional solving algorithms will not work. Longer bungees and more pieces bandaged would allow deeper knotting before the cube binds up. I've not heard of anyone here trying it, but solving it would undoubtedly be a daunting task

To stardust4ever:
thank you for your information & good sugestions.
I'll try later.
Would you show me the pictures?

This picture is from a post made by Dave.

Thank you for reply.

The concept of using rope on 3x3 is same as mine.
But there is a little difference. My rope is thru a ring while passing the 2nd corner. I don't want to fix the length of rope between 2 corners but total length among 3 corners. And I think the two designs will have different fun when solving them.

I change the rope and the ring.
I can solve it by using corner first method now,but fail by using edge first method and layer by layer method.
Is anyone interested to solve it?
It's easy to make and challenging.

can you take a picture from another angle of the cube ?

The other side

Cool idea! In that last picture it looks like it's attached to your phone!

-π (Eitan)