Sunflower v1

on 16 Oct 2021

hold on;axis off;

%% Stem - just a rectangle :)

patch(40*[-1,-1,1,1],-400*[1,0,0,1],[0,.5,0])

%% Petals - rose curve equations {rhodonea curves by Guido Grandi (1723-1728)}

t=0:.01:2*pi;% theta vector

for b=[0,pi/2]% angle of rotation

n=275*cos(6*t+b);

x=n.*cos(t+b);% amplitude = 250

y=n.*sin(t+b);% number of petals/2 = 6 (odd)

c=x.^2+y.^2>127^2;% max radius florets = sqrt(118 * 137.508) ~ 127

patch(x(c),y(c),[1,.8,.3])% color_petals = [1,.8,.3]

end

%% Florets - model proposed by H. Vogel (1979)

z=linspace(1,118,1200)*137.508;% golden angle = (3-sqrt(5)) * 180 ~ 137.508 [deg]

a=sqrt(z);

v=a.*cos(z);

w=a.*sin(z);

plot(v,w,'ok','MarkerFaceColor',[.4,.3,.1])% color_florets = [.4,.3,.1]