“Speedy Calculator”

Data:

• This spiral slide rule was mentioned in Skid Stick Issue #51, October 2015, page 8.
  It was originally published in a 2015 sales catalog by the company Tesseract (item #48).
• The inscription on the lid says: “Speedy Calculator, Bté. S.G.D.G.”
• 19" wide
• The device has two drums that can be rotated independently, and two pointers.

Questions:

1. Manufacturer?
2. When it was made?
3. etc.
   Usage probably similar to Wrights Arithmeter Andries de Man, Andreas Poschinger
   The 2 sharp pointers might be moved relative to each other by the right knob om the ruler. The left knob might be used to move them together. See detail photo in The Actuary Magazine Eamonn Gormley
   Compare patent FR1080809 issued to Henryk Milich in 1954 Andries de Man
   A rare item, it does not appear in Thomas A. Russo, “Antique Office Machines - 600 Years of Calculating Devices” published by Schiffer (ISBN 0-7643-1346-0). David Rance