create candidates 1000 cells allot
create temp 1 cells allot

: setones
	0 begin dup 1 swap cells candidates + ! 1 + dup 999 > until drop ;
setones

0 candidates ! 0 1 cells candidates + !


: findone
	begin 1 + dup cells candidates + @ 1 = until ;

: markmult
	temp ! 2 begin dup temp @ * cells candidates + 0 swap ! 1 + dup temp @ * 999 > until drop temp @ ;

: mainloop
	0 begin findone markmult dup 499 > until drop ;
mainloop

: printloop
	cr 0 begin dup cells candidates + @ 1 = if dup . S" is prime" type cr then 1 + dup 999 > until drop ;

printloop