an example can be found on AMOSPro_Examples:Examples/H-2/Help_25.AMOS
Rotates a colour downwards through the current screen palette.
Shift Down delay,first,last,flag
first and last choose the range of colour indexes which will be rotated by your instruction.
delay sets the delay in fiftieths of a second between each colour shift.
type =1 cycles the colours continuosly.
=0 discard the colour value of index first after each rotation.