a reticello is an old technique that comes from italy i think.. the old style has air bubbles under each overlay.. it is basically two layers of lines that go in opposite directins layed over top of themselves... one way to do it , tube or rod, is to
1 lay straight lines down a tube or rod... multiple colors or one color..
2. twist that segment one full rotation so that the original lines match up with eachother..
3 lay lines that match the start and end point of each one....
4 twist segment one half rotation the other direction...
5 carefully clean up the end so that all the lines meet up to a point...
5 flatten and add lens, blow out and use in segment, or implode... etc..
troy bennet does some of the nicest cleanest ratti marbles ive seen out there, as with josh sable...
http://www.glassartists.org/Gal12850..._Reticello.asp
hope this helps...
andrew