A small gift for a friend: Bottle opener with one of the most beautiful math equation on it

A memeber of our hackspace will move to another city, we decided to go hiking together. I thought it’s a good idea to make a special and unique gift for him. But which kind of gift?

I know he likes Math, so the idea of the bottle opener design from WAZER website with a math equation on it came to my mind. Euler’s identity is used because it’s simple and beautiful and not so big and long.

Here’s the result:

I wrapped it in a piece of tissue paper. After we walked a while I pulled the gift out of my backpack and said “I made a small gift for you” and passed it to him.

“Let me guess”, “Something made of metal?” He tried to figure it out while unwrapping the paper.
“Ah, e to i Pi plus 1 equals zero!”
“Do you like it?” I asked.
“Yes, of course. Thank you!” He replied.


I first downloaded the DXF in this page:

Then imported it into Inkscape to edit, but strangely I can’t ungroup the whole drawing thus can’t delete the “WAZER” texts.

Open it in LibreCAD, no luck:

QCAD interpreted the drawing correctly:

  • Deleted “WAZER” and saved the file.
  • Imported this file into Inkscape.
  • Googled a hand-written Euler’s identity image and also pasted it in Inkscape.
  • Traced the equation with the “Draw freehand lines” tool (“Create BSpline path” option selected and used 40 as the “Smoothing” value ).
  • Fine tuned the lines with the “Edit paths by nodes” tool.
  • Imported to WAM
  • Cut (Material: Stainless steel 304, thickness: 2.5mm)

Here you can see the first part I got, not quite well. I realized I forgot to count the kerf size in!

Counted the kerf size in and did a quick analyzation, adjusted some strokes. Finally I got a beautiful cut!

SVG file attached.


Hi Atommann,

What a masterful operation of Inkscape!

The process of turning hand-drawn curves into single cut path is really helpful!

I will try it on my end and see if I can turn it into a online article.