From British designer Ben Mazur, Swaybath is a revolutionary bath concept.

How does it work? The shower head above the tub fills it with water which is ultimately drained through a valve. The tub is made out of silicone. This material has the great advantage of shaping itself to the body of anyone taking the peaceful bath. That is why Swaybath has the ability to change sizes, according to the person that it holds inside.

It can also be stretched by modifying the bottom and sides.

via the design blog