Several functions produce interesting images providing nice decorations.
Repetition of the same forms can be provided by PERIODIC functions.
Here are some examples.
f(x,y)=x2+y2 MATLAB Script D.1
f(x,y)=(cos x)2+(cos y)2 MATLAB Script D.2
f(x,y)=cos(x3 + y3) MATLAB Script D.3
f(x,y)=sin(x2+y2) MATLAB Script D.4
f(x,y)=sin(x2+y2) MATLAB Script D.5
f(x,y)=sin[1/(x2+y2)] MATLAB Script D.6
f(x,y)=(tan x)2+(tan y)2 MATLAB Script D.7
f(x,y)=tan (x2+y2) MATLAB Script D.8