I was recently sent a link to:
Which has a host of pdf files with detailed instructions on all manner of geometric calculations. The focus of the site is animation for games programs, but there is plenty here of interest to engineers.
A small part of their listing is shown below (click for full size view):
 | Benata on Ana Vidović |
 | mindOnion on Drawing a Buckyball in Ex… |
 | dougaj4 on Drawing a Buckyball in Ex… |
| mindOnion on Drawing a Buckyball in Ex… |
| mindOnion on Drawing in Excel 7 – Cre… |
 | Veronica Davenport on Asymmetric Catenary Function |
| py_UMom spreadsheet… on More on combined shear and ben… | |
 | Skip on xlwings – dataframes and… |
| dougaj4 on xlwings – dataframes and… |
| More on combined she… on RC Design Functions 9.03; comp… | |
| skip on xlwings – dataframes and… |
| skip on mpmath for Excel |
| dougaj4 on mpmath for Excel |
| skip on mpmath for Excel |
| dougaj4 on Composite Beam Spreadsheet Upd… |
Newton Excel Bach, not (just) an Excel Blog 