Following on from my experiments with Pan & Crop Masks, I thought it would be fun to experiment with Vegas Pro's track compositing feature.
Here is an example of using "Add." There are two tracks with a Checker board pattern on Track One and a Blue Solid on Track Two.
The Movement of Track One is a keyframed effect called "Wave" which is added before Pan&Crop. The bottom track has the Saturation Adjust effect added to it with the "High" element animated.