Wave Interference

fastgraphics
clg
rem wave source coordetanes
x1=150 : y1= 300 : x2= 0 : y2=0
for n = 1 to 100 step .2
For x = 0 to 300 step 5
For y = 0 to 300 step 5
d1 = ((x-x1)^2+(y-y1)^2)^0.5
d2 = ((x-x2)^2+(y-y2)^2)^0.5
s1=60*sin(d1/5-n)
s2=60*sin(d2/5-n)
if 5*n>=d2 then
color rgb(122+s2,122+s2,122+s2)
else
color rgb(122+s1,122+s1,122+s1)
end if
if 5*n>=d1 and 5*n>=d2 then color rgb( 122+s1+s2, 122+s1+s2,122+s1+s2)
if 5*n<=d1 and 5*n<=d2 then color grey
circle x,y,3
next y
next x
refresh
next n