diff --git a/pdf/pdf.html b/pdf/pdf.html
index a26e4857741889a52cd21caa2c348f58eb5148a9..a0a26287c74f3554b76ae0233cdf36ae4c58e280 100644
--- a/pdf/pdf.html
+++ b/pdf/pdf.html
@@ -56,6 +56,8 @@ Acrobat Distiller (network version): 2495$
 
 ---
 
+# Releases
+
 |      | Year | Industry | Notable features |
 | ---- | :--- | :------- | :--------------- |
 | v1.0 | 1993 | Adobe | **text**, **images**, **pages**, **hyperlinks**, bookmarks | 
@@ -112,7 +114,7 @@ Single purpose, which is archived:
 
 <img src="images/sizing.png" width="60%">
 
-Comarison: How webpages deal with different devices:
+Comparison: How webpages deal with different devices:
 - Adapt font size, colors, spacing, ... to screen size
 - Adapt layout to aspect ratio / screen size
 - Remove or add elements depending on end device
@@ -314,6 +316,14 @@ Steps:
 
 => Requires deep knowledge about font
 
+---
+
+# The PDF wayâ„¢: Roll your own
+
+
+
+
+
 ---
 
 class: center, middle
@@ -322,8 +332,97 @@ class: center, middle
 
 ---
 
+# Introduction
+
+History:
+- Adobe `Type-1` (1984)
+- Apple `TrueType` (1991)
+- Microsoft & Adobe `OpenType` (1996)
+
+`OpenType` flavours:
+- `TrueType`-flavoured `OpenType` (`.ttf`)
+- `PostScript`-flavoured `OpenType` (`.otf`)
+
+Omnipresent.
+
+---
+
+# Table directory
+
+File starts like this:
+```
+0x00010000 || 12 || (...) || tables
+```
+
+`0x00010000` for TTF (or `0x4F54544F` for OTF)  
+`12` is number of tables  
+tables specify content
+
+Many tables, many functions.
+
+Have you tried typesetting مرحبا بالعالم?  
+What about suficient?
+
+---
+
+| Name | Purpose | 
+| ---- | :--- | 
+| cmap | character maps | 
+| maxp | memory requirements (#characters, #points, ...)
+| head | global information (max bounding box, font style, ...)
+| OS/2 | windows font metrics
+| name | multilingual strings about font (copyright notice, font name, ...)
+| cvt  | list of values for instructions
+| fpgm | program run upon first usage of font
+| gasp | "prefered rasterization on gray-capable devices"
+| prep | program run upon character drawing
+| GDEF | ligatures
+| GPOS | "glyph placement in sophisticated text layout"
+| GSUB | ligatures
+| hhea | sizing per glyph (ascender, decender, ...)
+| loca | offsets of glyph data blocks
+| hmtx | width of glyphs
+| glyf | list of glyph data blocks
+
+In short: Read out tables, patch them together differently, hope offsets work.
+
+---
+
+# Bonus: How to extend ttf?
+
+Steps:
+
+1. Just do it
+2. Wait until other vendors need to adapt
+3. Profit
+
+like colored glyphs (emojis!):
+- `COLR`, `CPAL` (microsoft + mozilla)
+- `CBDT`, `CBLC` (google)
+- `sbix` (apple)
+
+---
+
+class: center, middle
+
+# Reflection
+
+---
+
+# Reflection
+
+Success factors:
+- PDF specification was adapted to customer requests
+- TTF can be extended by anyone without breaking readers
 
+What about long term storage (PDF)?  
+- PDF specification is complex, large, organically grown
+- PDF destroys semantic meaning of source
+- Might not even able to recover text!
 
+Better Long-Term storage?
+- Word / Excel -> nearly same problems as PDF
+- HTML / CSS as structure stays -> but the "web" changes rapidly
 
 
     </textarea>
diff --git a/project management/project management.html b/project management/project management.html
index 9cd0c95b96217eac702da5400e7c40057c8bd8ac..bbdcecac355805885fb9e1983b8ff4810b63eccc 100644
--- a/project management/project management.html	
+++ b/project management/project management.html	
@@ -52,7 +52,7 @@ Nearly universally referenced issues:
 
 ---
 
-# Epirical data
+# Empirical data
 
 Unfortunately, mostly useless.