SET WINDOW -2.2,2.2,-2.2,2.2
SET LINE width 30
FOR t = 0 TO 10*PI STEP 0.05
   SET DRAW mode hidden 
   CLEAR
   FOR y = 0.1 TO 4 STEP 0.2
      FOR x = 0 TO PI STEP 0.2
         PLOT LINES: -1+SIN(t)/5+SIN(t)*SIN(y*PI/2)/4,-2+y;1+SIN(t)/5+SIN(t)*SIN(y*PI/2)/4,-2+y
      NEXT x
   NEXT y
   WAIT DELAY 0.01
   SET DRAW mode explicit
NEXT t
END