Difficulty : Beginner-Intermediate
Number of Bills : 1
Denomination Recommended : 1$
Any will do but the seals on the back of the 1$ or 2$ probably look best.
Credits : Originally found somewhere on the net. Credit on JPG shows as Joe Gilardi.

Diagram (1) [JPG]
Diagram (2) [JPG]
Diagram (3) [JPG]

Top
Butterfly 02-01
Front
Butterfly 02-02
Bottom
Butterfly 02-03