I feel the material that was used to cover the wood was very thin and would tear easily.  Due to the thinness of fabric and the smooth wood underneath, my car had a difficult time jumping around due the inability to attach her claws to the fabric and pull herself up. Also, the tallest tower is not flush with the rest of the boards alignment so I am unable to place it directly against the wall to help stabilize.  Side note, the material is soft and she likes jumping from tower to tower.