(    Turtle Graphics II, screen 1     )›DECIMAL›: VALUES›         <BUILDS  0 DO›              0 , LOOP›         DOES> OVER + +›              TO-FLAG @ IF› 0 TO-FLAG !  !  ELSE›              @  THEN ;›VALUE PREFIX›: SET   ( --- )  2 TO PREFIX ;›: SHOW   ( --- )  4 TO PREFIX ;›: ROOT:   ( --- )›          <BUILDS SMUDGE ]›  DOES> PREFIX + @ EXECUTE›               0 TO PREFIX :›-->››(    Turtle Graphics II, screen 2       )›4 CONSTANT #TURTLES›VALUE WHICH›  ( The number of the active turtle )›: ACTIVE!   ( n --- )   TO WHICH ;›: .WHICH   ( --- )›  ." Turtle #" WHICH . ;›  : ACTIVE?  ( --- )›     .WHICH ." is active " CR ;›ROOT: ACTIVE  WHICH ACTIVE! ACTIVE? ;›-->››(   Turtle Graphics II, screen 3        )›: MODE@   ( --- n )   87 C@ ;›: MODE?   ( --- )›   ." This is graphics mode"›                     MODE@ . CR ;›TABLE MAX_COL#   ( n1 --- n2 )›  39 , 19 , 19 , 39 , 79 , 79 , 159 , 159 , 319 ,›TABLE MAX_ROM#   ( n1 --- n2 )›  19 , 19 , 9 , 19 , 39 , 39 , 79 , 159 ,›: WHOLE-SCREEN  ( --- n1 n2 n3 n4 )›  1  MODE@ MAX_COL# 1-›  1  MODE@ MAX_ROW# 1- ;›-->››( 44 Turtle Graphics II, screen 4      )›: VIEWPORT@   ( --- n1 n2 n3 n4 )›  CLIPPING LEFT RIGHT TOP BOTTOM ;›: VIEWPORT?   ( --- )  CLIPPING›   ." The viewport is from column "›     LEFT . ." to " CR ." column "›    RIGHT . ." and from now " TOP .›           ." to row " BOTTOM . CR ;›VALUE XMIN          VALUE YMIN›VALUE XMAX          VALUE YMAX›: WINDOW@   ( --- n1 n2 n3 n4 )›  XMIN XMAX YMIN YMAX ;›: WINDOW?   ( --- )›     ." The window is from x=" XMIN .›   ." to X=" XMAX . CR ." and from Y="›            YMIN . ." to Y=" YMAX . CR ;›-->›››(    Turtle Graphics II, screen 5     )›VALUE 0COL           VALUE 0ROW›: ORIGIN!      ( --- )      CLIPPING›         XMIN MINUS  RIGHT LEFT -› XMAX XMIN -  */ LEFT +  TO 0COL›         YMAX MINUS  TOP BOTTOM -› YMAX YMIN -  */ TOP +  TO 0ROW ;›: VIEWPORT!   ( n1 n2 n3 n4 --- )›                      CLIPPING›  MODE@ MAX_ROW# MIN  TO BOTTOM›                  0 MAX  TO TOP›   MODE@ MAX_COL# MIN  TO RIGHT›                 0 MAX  TO LEFT›                        ORIGIN! ;›: WINDOW!   ( n1 n2 n3 n4 --- )›  TO YMAX  TO YMIN  TO XMAX  TO XMIN›                             ORIGIN! ;›-->››(     Turtle Graphics II, screen 6    )›ROOT: VIEWPORT›  VIEWPORT@ VIEWPORT!  VIEWPORT? ;›ROOT: WINDOW›  WINDOW@ WINDOW! WINDOW? ;›: LEFT-   ( --- n )›  CLIPPING LEFT 1- 0 MAX ;›: TOP-    ( --- n )›  CLIPPING TOP 1- 0 MAX ;›: RIGHT+  ( --- n )     CLIPPING›  RIGHT 1+  MODE@ MAX_COL#  MIN ;›: BOTTOM+  ( --- n )    CLIPPING›  BOTTOM 1+  MODE@ MAX_ROW# MIN ;›: FRAME    ( n --- )   COLOR›       LEFT-  TOP-       PLOT›       RIGHT+ TOP-     DRAWTO›       RIGHT+ BOTTOM+  DRAWTO›       LEFT-  BOTTOM+  DRAWTO›       LEFT-  TOP-     DRAWTO ;›-->››(     Turtle Graphics II, screen 7    )›#TURTLES VALUES PEN()›: PEN@    ( --- flag )  WHICH PEN() ;›: PENDOWN?   ( --- flag )   PEN@ ;›: PENUP?    ( --- flag )  PEN@ 0= ;›: PEN!    ( flag --- )›  0= 0=  WHICH  TO PEN() ;›: PENDOWN   ( --- )  1 PEN! ;›: PENUP    ( --- )   0 PEN! ;›: PEN?    ( --- )    .WHICH›  ." has her pen "  PEN@ IF›              ." down " ELSE›                ." up " THEN›                          CR ;›ROOT: PEN      PEN@ PEN! PEN? ;›-->››(    Turtle Graphics II, screen 8      )›#TURTLE VALUES INK()›: INK@   ( --- n )   WHICH INK() ;›: INK!   ( n --- )   WHICH  TO INK() ;›: ERASING  ( --- )   0 INK! :›: INK?    ( --- )›    .WHICH ." is using ink #" INK@ . CR ;›ROOT: INK   INK@ INK! INK? ;›-->››(    Turtle Graphics II, screen 9      )›#TURTLES VALUES HEADING()›: HEADING@   ( --- n )›  WHICH HEADING() ;›: HEADING?   ( --- )     .WHICH›  ." has heading " HEADING@ . CR ;›: HEADING!   ( n --- )›  360 MOD  WHICH  TO HEADING() ;›: TURNTO     ( n --- ) HEADING! ;›ROOT: HEADING›  HEADING@ HEADING! HEADING? ;›: TURN    ( n --- )›  HEADING@ + HEADING! ;›: RIGHT   ( n --- )   TURN ;›: LEFT    ( n --- )  MINUS TURN ;›-->››(    Turtle Graphics II, screen 10     )›#TURTLES VALUES X()›#TURTLES VALUES Y()›: X@     ( --- n )   WHICH X() ;›: Y@     ( --- n )   WHICH Y() ;›: X?     ( --- )›  .WHICH ." is at X=" X@ . CR ;›: Y?    ( --- )›  .WHICH ." is at Y=" Y@ . CR ;›: POSITION@   ( --- n1 n2 )  X@ Y@ ;›: POSITION?   ( --- )          .WHICH›   ." is at X=" X@ . ." and Y=" Y@ . CR ;›-->››(    Turtle Graphics II, screen 11    )›: X->COL    ( n1 --- n2 )   CLIPPING›  RIGHT LEFT - XMAX XMIN - */ 0COL + ;›: Y->ROW    ( n1 --- n2 )   CLIPPING›  TOP BOTTOM - YMAX YMIN - */ 0ROW + ;›: SCALE     ( n1 n2 --- n3 n4 )›  SWAP X->COL SWAP Y->ROW ;›: ?CONSOLE  ( --- flag )›  53279 C@ 7 = NOT ;›: POSITION!  ( n1 n2 --- )›                    ?CONSOLE IF›           SP! CR ." ok" QUIT THEN›                          PEN@ IF›                      INK@ COLOR›  OVER OVER SCALE   POSITION@ SCALE›                           LINE THEN›         WHICH TO Y()   WHICH TO X() ;›-->››(    Turtle Graphics II, screen 12     )›: GOTO   ( n1 n2 --- )   POSITION! ;›ROOT: POSITION›   POSITION@ POSITION! POSITION? ;›: X!   ( n --- )  Y@ POSITION! ;›: Y!   ( n --- )  X@ SWAP POSITION! ;›ROOT: X   X@ X! X? ;›ROOT: Y   Y@ Y! Y? ;›: MOVETO   ( n1 n2 --- )›  PEN@ ROT ROT PENUP POSITION! PEN! ;›: DRAWTO   ( n1 n2 --- )›  PEN@ ROT ROT PENDOWN POSITION! PEN! ;›  -->›››(   Turtle Graphics II, screen 13    )›VALUE SIZE_N     VALUE SIZE_D›: SIZE@    ( --- n1 n2 )›  SIZE_N SIZE_D ;›: SIZE*    ( n1 --- n2 )  SIZE@ */ ;›: SIZE!    ( n1 n2 --- )›  TO SIZE_D  TO SIZE_N ;›: SIZE?    ( --- )›              SIZE_D DUP . 1 = IF›                ." step is " ELSE›              ." steps are " THEN›  ." a distance of " SIZE_N . CR ;›ROOT: SIZE  SIZE@ SIZE! SIZE? ;›-->›››(   Turtle Graphics II, screen 14   )›: VECTOR   ( n --- n1 n2 )›   DUP HEADING@ SIN*  X@ +›   SWAP HEADING@ COS*  Y@ + ;›: FORWARD  ( n --- )›  SIZE* VECTOR POSITION! ;›: BACKGROUND  ( n --- )  MINUS FORWARD ;›: MOVE   ( n --- )›  PEN@ SWAP  PENUP FORWARD  PEN! ;›: DRAW   ( n --- )›  PEN@ SWAP  PENDOWN FORWARD  PEN! ;›-->›››(   Turtle Graphics II, screen 15   )›: PER-PIXEL    ( n --- )›                   CLIPPING >R›               RIGHT LEFT - 2 /›  DUP MINUS R *  SWAP 1+ R *›            BOTTOM TOP - 2 /›  DUP MINUS R *  SWAP 1+ R *›  SET WINDOW   R> 1 SET SIZE ;›( Make SURE you typed the >R and R> )›( in this correctly. )›: SCREEN-DEFAULTS   ( --- )›  WHOLE-SCREEN SET VIEWPORT›               100 PER-PIXEL ;›TABLE GR.BYTES   ( n1 --- n2 )›   960 , 400 , 200 , 200 , 400 ,›   800 , 1600 , 3200 , 6400 ,›: CLEAR   ( --- )›  88 @  MODE@ GR.BYTES  ERASE ;›-->›››(   Turtle Graphics II, screen 16    )›: HOME   ( --- )›  0 0 MOVETO  0 TURNTO  PENDOWN ;›: START  ( --- )›          #TURTLES 0 DO›     I SET ACTIVE  HOME›         MODE@ 2 MOD IF›   I ELSE  I 0= 0= THEN›           SET INK  LOOP›            1 SET ACTIVE ;›: MODE!   ( n --- )›  GRAPHICS  SCREEN-DEFAULTS›             1 FRAME  START ;›ROOT: MODE  MODE@ MODE! MODE? ;›: NEW  ( --- )  CLEAR 1 FRAME  START ;›: BYE  ( --- )  0 GRAPHICS›       0 710 C!  68 712 C! ;›-->›››(   Turtles Graphics II, screen 17    )›: DEFINE  [COMPILE] :  : IMMEDIATE›: AS ; IMMEDIATE›: END   [COMPILE] ;  ; IMMDEIATE›: \   ( ignores rest of line )›  IN @ C\L / 1+ C/L * IN ! ; IMMEDIATE›: (›  COMPILE 0  [COMPILE] DO ; IMMEDIATE›: )  [COMPILE] LOOP ; IMMEDIATE›: +)   [COMPILE] +LOOP ; IMMEDIATE›:S››