dev.new()
###漸化式プロット****
#library(rgl)
#rgl.bg(color="black")
x1=0.1;y1=0.1
plot(x1, y1,xlim=c(-10,15),ylim=c(-10,10),bg="blue")
n=5
for (i in 1:60000){
######## 
 switch(n,               # switch(整数,
   {a=0.55;b=-1.00025;c=2.5
    x2=y1+a*x1+b+c/(1+x1^2)
    y2=b*x1　　
 　　　fm<-paste("x2=y1+a*x1+b+c/(1+x1^2)","　　y2=b*x1")},  # 1 のときに実行
   {a=-0.99;b=1;c=4.8
    x2= a*x1+b*y1+c/(1+x1^2)-4.55
　　　　y2=x1*a
    fm<-paste("x2=a*x1+b*y1+c/(1+x1^2)-4.55","　　y2=x1*a")}, # 2 のときに実行
   {a=1;b=0.87;c=1
    x2=a*x1-b*y1-c/(x1+1)
    y2=b*x1+0.1*x2 
    fm<-paste("x2=a*x1-b*y1-c/(x1+1)","　　y2=b*x1+0.1*x2")}, #   3 のときに実行
    {a=2.5;b=-3;c=1
     x2=a*sin(x1)+b*cos(y1)
  　  y2=a*x1+c*x2                                            #  4
     fm<-paste("x2=a*sin(x1)+b*cos(y1)","  y2=a*x1+c*x2")}, 
   {a=-1.26;b=1.00;c=4
     x2=a*x1+b*y1+c/(1+x1^2)
  　  y2=-b*x1                                                #  5
     fm<-paste("x2=a*x1+b*y1+c/(1+x1^2)","  y2=-b*x1")} 

 )
####### 
par(new=T)
cl=1-i%%255/255
cl1=i%/%2000
par(cex=0.2)
#plot(x2, y2,xlim=c(-10,15),ylim=c(-10,10),col=i,type="p",pch=20,ps=2)
points(x2, y2,col =cl1,ps=1)
#points(x2, y2,col = "#3A00ff50")
x1=x2;y1=y2
}
par(cex=1);
pa<-paste("a=",a,"  b=",b,"  c=",c)
mtext(pa,1,0,col=2)
mtext(fm,3,0,col=4)

title("漸化式表示")
x2;y2