-- math functions to generate decorative image patterns
-- decorated line
-- by Kaneyuki Miwa
-- (use Radians)

boundize(x) = (x/(0.9+abs(x))+1)*0.5
tex1_1(x) = y:=x*8+0.5,y-trunc(y)

--- Imaging function
f(x,y) = r:=exp(-y),
         fr:=r*cos(x)+1,
         fi:=r*sin(x),
         l:=fr^2+fi^2,fr:=1-2*fr/l,fi:=2*fi/l,
         (tex1_1(boundize(fi+fr))+tex1_1(boundize(fi-fr)))/2

--- Imaging domain
Xmin = -2*pi; Xmax = 2*pi; Ymin = -pi; Ymax = pi

--- Imaging resolution
xpixels = 160; ypixels = 80

--- Imaging 
Zmin = 0;Zmax = 1
F[i,j] = f(Xmin+(i-0.5)/xpixels*(Xmax-Xmin),
           Ymin+(j-0.5)/ypixels*(Ymax-Ymin)) dim[xpixels,ypixels]
image F