"in terms of X and Y the second cascade is 2x the width and height of the first cascade and is located 1 unit to the right and 2.25 units upwards. Using that, you could project using the first cascade matrix and then apply the appropriate offset and scale to get coordinates in terms of the second cascade."
I'm having a hard time understanding where those numbers come from and how I would obtain my sample coordinates from that.
I think he's just using those numbers from the example he drew. Not sure about the 2.25 units upward (seems like 0.75 units upward from the illustration). I *BELIEVE* the point of this example was to show that for subsequent cascades beyond the first, you could obtain the correct values by transforming with cascade 0's matrix and then applying a transform, rather than requiring N cascade matrix transforms.