Morie Pattern (July 27, 2010)

# morie pattern - j.m.reneau 2010-07-27

# height of pattern
h = 500
# width of pattern
w = 500
# distance between lines ((w or h)/s) on edge
s = .005

fastgraphics
graphsize w,h

# background
color black
rect 0,0,w,h

x0 = w/2
y0 = h/2
for t = 0 to 1  step s
   x1 = 0
   y1 = t*h
   gosub drawline
   x1 = w
   y1 = h-t*h
   gosub drawline
   x1 = w-t*w
   y1 = 0
   gosub drawline
   x1 = t*w
   y1 = h
   gosub drawline
next t
end

drawline:
dx = x0 - x1
dy = y0 - y1
# distance along length of line between points (as % of line length)
sl = 3  / ((dx ^ 2 + dy ^ 2 ) ^ .5)
for d = 0 to 1 step sl
   # color of pixel along line
   color rgb(255*d, 255*d, 255*d)
   plot x0 + dx * d, y0 + dy * d
next d
refresh
return