## A Scenes used during experiments

Figure 5: Images “urchin (8)” and “Sierpinski (3)” |

### A.1 Urchin

The scenes in experiments U are made of small cylinders
arranged into a spheric shape, yielding a stylized sea urchin —
see the first image of Figure 5.
At order *n*, there are 2^{n} cylinders.
The “urchin” scenes achieve a reasonably high level of complexity
in rendering, since there are many intersections to compute, still at
a moderate price in memory and scene building time.

### A.2 Decaying Sierpinski cube

The scenes in experiments S are decaying Sierpinski cubes of
increasing order — see the second image of Figure 5.
The Sierpinski cube of order *n* normally contains 20^{n} small cubes.
In our “decaying” version we erase 2 sub-elements out of 7 at
every induction step, and apply pseudo-random rotation and scaling
As a result, we obtain a slightly chaotic image
made of approximatively 14.2^{n} elementary cube.