Some Pretty Amazing Soap Swirling

So...I was looking over some other soap maker's blogs and came across this one: Alkali Soaps
Scroll down about half way and look at some of the swirls. Amazing! I was trying to figure out how she did the three part swirl in the log mold. It reminded me of a discussion we had on the Candle and Soap Making Forum this week about how to do vertical layers in candles. You have to figure out what the parts of the candle (or soap) are...and then figure out how the soap/candle maker got them to be where they are.
BUT...as I was looking closely at some of the photos (click on the photo to bring it up super size) it looked almost like the swirl was just on the TOP of the bar - like a 1/4" layer on the top. Hmmm....very interesting. So what I think we're seeing in the photos is not a log mold...but rather a rectangular "slab" mold that she pours a base color into...and then can play artistically on the top layer. Perhaps with some sort of dam system that divides the two colors. Then lay in the dark color, take out the dams...and swirl away. Very cool! You can best see it in this picture. It's kind of like a Napoleon Pastry. I am definitely going to have to try this.