graphsize 800,800
fastgraphics
offset=0.5: dt= 0.01: colbkg = rgb(0,0,0,20)
while true
	color colbkg
	rect 0,0,800,800
	color green
	t2=offset
	for t1 = 0 to 75 step dt
		plot (f(t2),f(t1))
		t2=t2+dt
	next
	refresh
	offset=offset+0.0015
end while

function f(x)
	f=400+150*(sin(pi*x)+sin(4.5*x))
end function