Reference:Cubic Pattern

The cubic pattern takes six texture elements and maps each one to each of the six pyramids centered at each half-axis, effectively mapping each texture element to each side of a origin-centered cube.

The cubic pattern and the order of texture elements The first group of elements map to the positive half-axis, in the X, Y and Z axes respectively. The same order is applied to the last group of elements, except on the negative half-axis.

The syntax is:

texture {
  cubic
    TEXTURE_ELEMENT_1
    ...
    TEXTURE_ELEMENT_6
  }