(b) 0 0 50 50 makesymbol  (a) 0 0 makeinstance (b) 75 75 makeinstance  (a) 300 200 makeinstance (b) 375 275 makeinstance (c)0 0 25 100 makesymbol (a) 0 0 100 100 makesymbol (a)open (c) 0 0 makeinstance  (c) 30 0 makeinstance (c) 75 0 makeinstance (Top)open