theta<-seq(0,2*pi,0.01) 
radius<-3

plot(NULL,xlim=c(0,10),ylim=c(0,10),axes=FALSE,xlab="",ylab="")

a<-3;b<-6
x<-radius*cos(theta)
y<-radius*sin(theta)
colours1<-c("blue","red","darkgreen","orange")
centres<-list(c(a,a),c(a,b),c(b,a),c(b,b))
for(i in 1:4){
lines(x+centres[[i]][1],y+centres[[i]][2],lwd=3,col=colours1[i])
}




##### ellipses with plotrix

install.packages("plotrix")
library(plotrix)
colours1<-c("blue","red","darkgreen","orange")
c<-140; d<-220
angles<-c(c,c-5,d,d+5)


plot(NULL,xlim=c(0,10),ylim=c(0,10),axes=FALSE,xlab="",ylab="")
a<-3;b<-5
centres<-list(c(a,a),c(a+0.2,b),c(b,a),c(b-0.2,b))
for(i in 1:4){
draw.ellipse(centres[[i]][1],centres[[i]][2],a=4,b=2,angle=angles[i],deg=TRUE, border=colours1[i],col=NA,lwd=3) 
}

colours1<-c("blue","red","darkgreen","orange")
colours2<-list(c(0,1,0,0.3),c(1,0,0,0.3),c(0,0,1,0.3),c(1,0.5,0,0.3))
c<-140; d<-220
angles<-c(c,c-5,d,d+5)
a<-3;b<-5
centres<-list(c(a,a),c(a+0.2,b),c(b,a),c(b-0.2,b))


##### colouring the zones with transparency=0.3 using rgb
plot(NULL,xlim=c(0,10),ylim=c(0,10),axes=FALSE,xlab="",ylab="")
for(i in 1:4){
r<-colours2[[i]][1]; g<-colours2[[i]][2];bl<-colours2[[i]][3]
draw.ellipse(centres[[i]][1],centres[[i]][2],a=4,b=2,angle=angles[i],deg=TRUE, border=colours1[i],col=rgb(r,g,bl,0.3),lwd=3) 
}