The use of the Parameter controls is very dependent on the selected
pattern. See Pattern for more information.
The range for both Parameter controls is -999 to 999.
Note that when the Parameter is used for the initial value as listed
in the Pattern Characteristics
least one of the two values should be something other than 0. When
both values are 0 the image is filled in with a single uniform color
so it appears to be basically blank. The reason that the default
values are 0, 0 is because the default Pattern is 1. In Pattern 1
the Parameter selects the hidden functions and in the default values
the hidden functions are turned off by setting them both to 0.