Developing the Swiss ball

So i started with drawing the Swiss ball chair i had found on the internet, sketching up new ways i could possibly improve the design. One of the limitations i found was that the ball is actually kept in place by the plastic ring. So i quickly drew up a sketch where the entire ball is free to move in any direction, finding that this resulted in a quite dangerous looking chair for those slightly unbalanced. The next design i came up with was less scary looking, as the ball is flattened it creates a larges surface to roll on and lessening the possibility of rolling right off.