Vase with tire: with tips to easily cut and rotate the tire

In this tutorial I teach you how to make a beautiful potted plant with an old penguin. I also teach a very easy technique of cutting and turning the tire. The base of the vase is made of cement and polystyrene foam.
Cement and polystyrene foam recipe:
1 measure of cement
1 AC2 mortar measure (mixture used to glue ceramic floors)
1 measure of crushed polystyrene foam
Sufficient water
As a measure I used a 2 liter plastic pot.
Thank you!