\ LIFO made FIFO \ ( X1 .. Xn n -- Xn .. X1 n ) : reverse >r sp@ sp@ r@ cells + \ ( bot-addr top-addr ) begin over over < \ bot top cross each other? while \ no dup @ >r \ save top-cell content over @ over ! \ replace top-cell over r> swap ! \ replace bot-cell cell- swap cell+ swap repeat 2drop r> ;