Add to turtle graphics demo

src/scripts/hrturtle.4th

@@ -29,4 +29,26 @@ SRC" TURTLE.4TH"
     10 +LOOP
 ;
 
+: ZOOM
+    361 0 DO
+        I MOVE
+        -122 TURN
+    5 +LOOP
+;
+
+: SPIRAL
+    361 0 DO
+        I 4 / MOVE
+        20 TURN
+    LOOP
+;
+
+: CLEAR 0 0 279 159 HGRRECT ;
+
+: CLEARTO HGRCOLOR 0 0 279 159 HGRRECT ;
+
+: INVERT 0 0 279 159 HGRXORRECT ;
+
+: RESET PENUP 140 80 MOVETO 0 TURNTO PENDOWN ;
+
 SHOW SPIN