FOR counter = startvalue DOWNTO endvalue [STEP stepvalue]
    [statement block]
NEXT [counter]

This has been added for FOR loops that count down, which are ambiguous when startvalue or endvalue are variables.

PRINT "counting from 3 to 0, with a step of -1"
FOR i = 3 DOWNTO 0 STEP 1
        PRINT "i is "; i
NEXT i