Formula Driven Graphics and Sound Demo (Guess the Formula)

My favourite one so far.

Computer will oddtonomically create a formula. Sound and video is based on this. Every 10 seconds some new operands are added. Help me out, what is the formula?

Sound formula has the following values:
x = position in file
y = channel +1
z = 1
NOTE: Sound amplification eases in and out to avoid high pitched squel noises.

Graphics formula has the following value:
x = position x
y = position y
v = red/green/blue 1/2/3
v = has an additional formula either v = v + position, or v = v - position or v = v * position

There are 9 operands
1. Add
2. Subtraction
3. Multiply
4. Divide
5. Sin of
6. Log of
7. Cosine of
8. Square Root
9. Power