SET bitmap SIZE 700,311.1
INPUT PROMPT "何番目？":d
SET WINDOW 0,3^d,0,3^d*4/9
LET a=0
PLOT LINES:0,0;
LET x=1
LET y=0
PLOT LINES:x,y;
FOR k=1 TO 4^d
   LET s=k
   DO
      LET s=s/2
      IF NOT(s=INT(s)) THEN EXIT DO
      LET t=t+1
   LOOP
   IF t/2=INT(t/2) THEN
      LET a=a+PI/3
   ELSE
      LET a=a-2*PI/3
   END IF
   LET t=0
   LET x=x+COS(a)
   LET y=y+SIN(a)
   PLOT LINES:x,y;
   WAIT DELAY 0.01
NEXT k
END