They look quite complex but are really pretty easy to make. The toughest part is the sanding.
These bowls can look incredible when cut from a nice hardwood with lots of figure. You can also do glue-ups of different species to make patterns in the bowl.
Sometime around 2009 or 2010 Carole Rothman published a book taking the technique to a whole new level. In her book she has designs of several different bowls. If you are interested in this technique you should certainly find her book. Here is a link to her book on Amazon.
Click book to purchase.
This book is only available in digital format. There will be a link on the final payment page that directs you to the download page. I will also send an automated email with the link to the download page.
If you would like to have all the patterns in the Scrollsaw Workshop catalog you can buy the first six years DVD and the 2013 update DVD at this link. DVD #1 is $20 and contains over 1,100 patterns. The 2013 update DVD is $7.50 and has another 178 patterns. The 2014 update DVD is $7.50 and has another 223 patterns.