: forward-difference
dup 0
?do
swap rot over i 1+ - 0
?do dup i cells + dup cell+ @ over @ - swap ! loop
swap rot
loop -
;
create a
90 , 47 , 58 , 29 , 22 , 32 , 55 , 5 , 55 , 73 ,
: test a 10 9 forward-difference bounds ?do i ? loop ;
test