library(plotrix)
distance<-function(x1,y1,x2,y2) { sqrt((x2-x1)^2+(y2-y1)^2) }
x<-c(103,31,115,75,40,101,70,75)
y<-c(22,105,49,34,79,85,96,90)
y<-150-y
angle<-c()
for(i in 1:8) angle<-c(angle,atan2(y[i]-75,x[i]-75))
par( mfrow = c( 2, 4 ), mai=c(0,0,0,0) )
for(n in 1:8)
{
	plot(x,y,xlim=c(0,150),ylim=c(0,150),asp=1,lwd=3,col="lightgray", axes = FALSE, xlab="", ylab="")
	points(x[n],y[n],col="red",lwd=3)
	for(i in 1:8) draw.circle(75,75,distance(75,75,x[i],y[i]),nv=1000,border="lightgray")
	draw.circle(75,75,distance(75,75,x[n],y[n]),nv=1000,border="red")
	segments(75,75,x[n],y[n],col="blue")
	segments(75,75,75+60*cos(angle[n]),75+60*sin(angle[n]),col="red")
	draw.circle(75+73*cos(angle[n]),75+73*sin(angle[n]),10,col="yellow")
	for(i in 1:length(alpha))
	    text(75+73*cos((pi*2)*((33.5-i)/26)), 75+73*sin((pi*2)*((33.5-i)/26)), LETTERS[i])
}