Keep doing it exactly the way you are doing it but make the following changes :


To "Mirror Image" (Left to Right)
Instead of doing your loops "For x = 0 to Len(y)" do it "For x = Len(y) to 0 Step -1".

What this does is starts from the end and works to the beginning while still working from right to left... effectively however you have reversed the wave.

To "Invert Image" (Turn upside down)
Instead of making the value sit (X pixels up) you need to negate it (ie -X pixels up).

What this will do is that all positives are negative and all negatives are positive. This means you have effectively turned your graph upside down.


Hope it all helps