Williams, Walt: Nu-Trix With the Square Circle ©1950 (circa) Boss Magic Co., IL Softcover, saddle-stitched, 5.5x8.5", 16 pages

Image courtesy Conjuring Arts Research Center

Comments: How to build a collapsible Square-Circle apparatus and ideas on its use

Contents:

1 Prologue (Bill "Dorny" Dornfield)
2 Introduction: how the apparatus came to be
3 How to Make It: a foldable Square Circle design, with changeable front-piece

7 Special Occasions:
8 Spring: for flower productions
11 Christmas: routine, setting a trap for Santa
14 Fourth of July: idea
14 Halloween: idea
14 Washington's Birthday: idea
15 A Special Production Item: modification of production container so it can be shown all around
16 Additional Idea (Russ Walsh): adding a door to the apparatus