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 table, at 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.