The Olivetti Summa 15 adding machine

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  • Опубликовано: 10 сен 2024

Комментарии • 7

  •  Год назад +2

    great video! interesting machine

  • @johnnycats5157
    @johnnycats5157 Год назад +2

    the yellow joystick selector is awesome

  • @franciscom.e.9780
    @franciscom.e.9780 Год назад +1

    I have several Olivetti typewriters, but mechanical calculator… yet.

  • @GrumpyTim
    @GrumpyTim Год назад +2

    Typically for Olivetti that's a beautiful machine Jaap - I wonder why they dropped the multiplication counter when they did the Prima Summa 20, that seems like a brilliant feature. Great video, you should get plenty of views on this one as the Olivetti machines have a big following.

    • @stephenfreeborn
      @stephenfreeborn Год назад

      Yeah, I hadn’t seen that counter. You can sure pick out an Olivetti across the room.

  • @user-js1yn6jc2o
    @user-js1yn6jc2o Год назад

    Apologies for the unrelated comment! Regarding the Chasing the Lights method for LightsOut, there are pattern tables online which have the corresponding top buttons to press for 3x3,4x4,5x5,6x6,9x9, but I was wondering if it was possible to find a pattern table for 7x7 and 8x8, and how would I go about finding pattern tables for n size boards?

    • @jaapsch2
      @jaapsch2  Год назад

      It is briefly explained on my Mathematics of Lights Out page in the section about the Pseudo-inverse.
      www.jaapsch.net/puzzles/lomath.htm#inverse
      On a blank board, see what light pattern you get on the last row if you press just one button on the top row and chase the lights down. Do this for each top row button. Build a matrix where the n-th matrix row is the light pattern corresponding to pressing the n-th button of the top row. Invert that matrix using standard Gaussian elimination (modulo 2) and then the rows of the resulting matrix is the pattern table you are looking for.