10  HGR 
20  GOSUB 200
30  GOSUB 300
90  END 
200  HCOLOR= 1
210  FOR Y = 90 TO 159  STEP 4
220  FOR X = 0 TO 279  STEP 8
230  HPLOT X,Y TO X +3,Y
240  NEXT X,Y
250  FOR Y = 92 TO 159  STEP 4
260  FOR X = 5 TO 276  STEP 8
270  HPLOT X,Y TO X +3,Y
280  NEXT X,Y
290  RETURN 
300  HCOLOR= 3
310  FOR D = 0 TO 3.14159  STEP 0.02
320 X = 139 -35 * COS(D)
330 Y = 90 -20 * SIN(D)
340  HPLOT X,Y TO X,140
345  IF  INT(Y) < > INT(OY)  THEN  PRINT "(x,y)="; INT(X);","; INT(Y):OY = Y
350  NEXT D
360  RETURN