: XYPOS [ GRID_MEM LITN ] ;
: _cl* COLS LINES * ;
: AT-XY ( x y -- ) LINES * + _cl* MOD XYPOS ! ;
'? NEWLN NIP NOT [IF]
: NEWLN ( ln -- ) COLS * DUP COLS + SWAP DO 0 I CELL! LOOP ;
[THEN]
: _lf
    XYPOS @ COLS / 1+ LINES MOD DUP NEWLN
    COLS * XYPOS ! ;
: _bs 0 ( blank ) XYPOS @ TUCK CELL! ( pos ) 1-
    _cl* MOD XYPOS ! ;