Rem the purple wave is made out of two simple sinusoidal waves. Change the frequencies and amplitudes and see what happens .

fastgraphics

Amplitude1=30

Frequency1=2

Amplitude2=30

Frequency2=8

for t = 1 to 1000 step .1

clg

for n = 1 to 31.4 step 0.1

r=Amplitude1*sin(t )*Sin(n/(10/Frequency1))

b=Amplitude2*sin(t )*Sin(n/(10/Frequency2))

p= r+b

color red

circle 10*n,r+250,3

color blue

circle 10*n,b+200,3

color purple

circle 10*n,p+100,3

next n

refresh

next t