All values are displayed in hexadecimal.
The keys i and d increase or decrease the step size which runs from 1 to 32.
The default step size of 15 (0F) produces 18 patchs; 5 produces 52, 3 produces 86, and 1 produces 256.
The keys a and z or - and + decrease or increase the background from 000000 (black) to FFFFFF (white).
The keys b and w set the gray patch to black and white respectively.
The bar below shows current gray level @ current step size.
