# シオマネキ
# http://i.imgur.com/uBTnujq.png
H=(sqrt(5+2*sqrt(5)))/2
A=0.5+0i
B=A+r

shiomaneki <- function(x,y){
xy=x+y*1i
(abs(xy-A)+abs(xy-B)+x)*2 + 1
}
x=seq(0,Re(B),length=100)
y=seq(0,H,length=100)
z=outer(x,y,shiomaneki)
contour(x,y,z,nlevels=20,lwd=2,bty='l')
x11() ;persp(x,y,z, theta=35, lty=3,col="lightblue",xlab='x',ylab='y',zlab='z',
ticktype='detailed',shade=0.75,phi=30,ltheta=-10,border=TRUE)
rgl::persp3d(x,y,z,col='blue')

sio <- function(xy) shiomaneki(xy[1],xy[2])
optim(c(0.4,0.4),sio,method='Nelder-Mead')