We created the model using an implicit function of a cylinder plus noise for the stump and an extruded 2D image for the roots. More visually compelling root systems can be created with procedural techniques such as L-systems, but for our application this trick is quick and gives control of root shape and placement to the user. A layer is applied over and between the roots using the precedence operator described earlier. The layer is procedurally divided into bricks and dirt to form the paving pattern.