BF=2.3; HF=2.3
BOXW(3,17,4,18)    # a window without margins
phrase <- "press ESC to stop the animation"
while(TRUE){
polyC(c(-10,30,30,-10),c(30,30,-10,-10),"yellow")
polyC(c(17,11,9,9,8,8,7,6,4,4,5,6,5,6,7,7,8,10,17),
   c(16,16,14,17,14,17,14,10,7,6,5,6.2,5,5,6,7,8,9,7),"grey")
polyL(c(10,11,11), c(9,10,11), "brown"); polyL(c(6,7,8,7,9,9), c(10,13,14,10,10,14), "brown")
polyL(c(10,10), c(15,11), "brown"); polyL(c(11,11), c(16,12), "brown")
polyL(c(12,12,9), c(16,13,10), "brown"); polyL(c(16,16,13,16), c(16,13,10,13), "brown")
polyL(c(13,13), c(16,10), "brown"); polyL(c(14,14), c(16,11), "brown")
polyL(c(15,15), c(16,12), "brown")
circleC(5,6.5, 0.25, "brown")
text(10,4.2,phrase,cex=0.8); attendi(1)
polyC(c(-10,30,30,-10),c(30,30,-10,-10),"yellow")
polyC(c(17,11,9,9,8,8,7,6,4,4,4.7,6,5.3,6,7,7,8,10,17),
   c(16,16+1,14+1,17+1,14+1,17+1,14+1,10+1,7+1,6+1,5+1,6.2+1,5+1,5+1,6+1,7+1,8+1,9+1,7),"grey")
polyL(c(10,11,11), c(9+1,10+1,11+1), "brown")
polyL(c(6,7,8,7,9,9), c(10+1,13+1,14+1,10+1,10+1,14+1), "brown")
polyL(c(10,10), c(15+1,11+1), "brown"); polyL(c(11,11), c(16+1,12+1), "brown")
polyL(c(12,12,9), c(16+5/6,13+1,10+1), "brown"); polyL(c(16,16,13), c(16+1/6,13+1,10+1), "brown")
polyL(c(13,13), c(16+2/3,10+1), "brown"); polyL(c(14,14), c(16+3/6,11+1), "brown")
polyL(c(15,15), c(16+1/6,12+1), "brown")
circleC(5,6.5+1, 0.25, "brown"); text(10,4.2,phrase,cex=0.8); attendi(1) }