Doughnut with pistachio topping
# Uniform sample of size n=300 in the annulus B(c, 0.5)\B(c, 0.25) # with c=(0.5, 0.5). n <- 300 theta<-runif(n,0,2*pi) r<-sqrt(runif(n,0.25^2,0.5^2)) x<-cbind(0.5+r*cos(theta),0.5+r*sin(theta)) # alpha-shape ashape.obj <- ashape(x, alpha = 0.1) #Plotting the alpha plot(ashape.obj, wlines= "vor", col = c(4, 1, 2, 3), lwd = c(1,3))
Castells 
