spiral2 pattern creates a double spiral that winds around the z-axis similar to
except that it has two overlapping spirals which twist in opposite directions. The result sometimes looks like a
basket weave or perhaps the skin of pineapple. The center of a sunflower also has a similar double spiral pattern. Its
Number_of_Arms value determines how may arms are winding around the z-axis. As a normal
pattern, the syntax is
spiral2 Number_of_Arms [, Bump_Size]
Number_of_Arms value is a required parameter but the float
which follows is optional.
Note: the comma is required especially if Bump_Size is negative. The pattern
triangle_wave wave type by default but may use any wave type.