3 pencolor
2 penmode
save

/b {-10 -10  moveto
    -10  10  lineto
     10  10  lineto
     10 -10  lineto
    -10 -10  lineto
} def

400 200 translate

20 { b
     fill
     5 rotate
     1.1 1.1 scale
   } repeat

restore
0 penmode