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Author: khoitsma

Structural engineer, Python programmer

Short Takes

  • khoitsma
  • General, List, Personal
  • 0 Comments

How big is 52 factorial?

Short Takes was last updated on August 21, 2025

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Poetry 1 May 2022

  • khoitsma
  • Observation, Personal, Poetry
  • 0 Comments

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Pipe Stress Calculus May 2022

  • khoitsma
  • Calculus, Concept, Engineering, Mathematics, Petrochemical Design
  • 0 Comments

In structural engineering and in pipe stress, is it possible to optimize designs using current software?

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Refining — 100th Anniversary of HP magazine May 2022

  • khoitsma
  • General, Petrochemical Design
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A rich and interesting history

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Excel — Taming of the Shapes with PyXLL May 2022

  • khoitsma
  • Concept, Excel, Python, PyXLL, Video
  • 0 Comments

Using PyXLL, I have programmed automatic shapes in Excel. That is, I built a function that draws an arbitrary shape in a user spreadsheet: the shape is defined by a range of coordinates; as the coordinates are edited, a new shape can be drawn.

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Powerful Song(s) Apr 2022

  • khoitsma
  • General
  • 0 Comments

In the 45 or 50 years since these songs were written, it has only accelerated

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Older posts
Newer posts

Recent Posts

  • The Triangle of Minimum Perimeter Nov 2025
  • NotebookLM Cather Oct 2025
  • Minimal Footprint Dropdowns in Excel Oct 2025
  • Bow Out Aug 2025
  • Automated Foundation Rebar Drawing Aug 2025
  • Close Encounters in Batting Averages July 2025
  • 2D Engineering Interpolation Jun 2025
  • Lessons Learned (structural engineering) Apr 2025
  • Marimo Notebook Mar 2025
  • Fixed Fixed Beam with a Moment at any Point — Superposition Mar 2025
  • NotebookLM Feb 2025

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Instant Access to all Posts
Short Takes
My Dash apps

My GeoGebra app
What is the most general equation for the area of a triangle?
The Wait calculation
The incessant obsolescence postulate (IOP)
Barnard’s Star and the 'Wait Equation'
IOP counterargument
The amazing arbelos (only good on a real desktop)
Surprises found in the arbelos (1954)
Arbelos from Wolfram MathWorld
Circle Theorems
• Circle Theorems Marked
• Circle Theorems — Practice
Two Semicircles
Japanese temple geometry
★ Sister Celine — a beautiful life
★ John Lienhard IV on Ingenuity
★ Charles Stutzenbaker, Field Biologist
Neal Stephenson on the OS
A few quotations

Tyler TX weather • 🌡 Steve Fitzgerald
Tyler TX weather • 3-day history
Tyler TX weather • calendar month
Tyler TX weather • graph month
East Texas weather • TAMU
★ All of the water in the world

Hacker News (from YCombinator)
Diaorifa
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Pentagonal number visual proof

Dice Distribution (bar)

Bayes theorem visual proof

Bayes icon