It's squishy, it's flexible, it stretches, it bounces, it blends, it's 3D Printed Black Elasto Plastic!!!!!

Squishy SpringBall by Opresco
Black Elasto Plastic is our first fully flexible material! It is still in the
experimental stages of development, and we are learning more about the
possibilities and restrictions of this material each and every day.
Design, order and give us feedback when your model arrives at your
doorstep! This material will be on trial until the July 20th, 2012,
so get your orders in soon. After the trial, we will review and decide
whether to introduce it permanently, whether we need to change any
design rules, etc.
Flexible Design Rules.

As this material is still in its very early stages of development, we rely on
your feedback to improve our design guidelines (email Nancy from the
Contact Us Page
with feedback). Right now, we can make the following suggestions but
please be aware that
these rules are flexible and subject to change as we learn more and
more about this amazing material and how to design for it.
Minimum wall & detail: 1.5mm
Minimum clearance: 1.5mm
Minimum hole size for hollow parts: 6.5mm (in diameter)
Check out our Black Elasto Plastic gallery, products available in this squishy material right now: