Update

aliasing.md

@@ -2,7 +2,19 @@
 
 Aliasing is a certain mostly undesirable phenomenon that distorts signals (such as sounds or images) when they are [sampled](sampling.md) [discretely](discrete.md) (captured at periodic intervals) -- this can happen e.g. when capturing sound with digital recorders or when [rendering](rendering.md) computer graphics. There exist [antialiasing](antialiasing.md) methods for suppressing or even eliminating aliasing. Aliasing can be often seen on small checkerboard patterns as a moiré pattern (spatial aliasing), or maybe more famously on rotating wheels or helicopter rotor blades that in a video look like standing still or rotating the other way (temporal aliasing, caused by capturing images at intervals given by the camera's [FPS](fps.md)).
 
-The following diagram shows the principle of aliasing:
+A simple example showing how sampling at discrete points can quite dramatically alter the recorded result:
+
+```
+' ' ' '.'- - .  |           .--.           '''''   |
+   . '  |      '|.        .'    '.             |   |
+-|- - -O+ - -O- -  '     |  O  O  |        ----+---'
+||     \|_ _ /     |     |  \__/  |        |   |
+|  ' .  | _ _ _._'        '.    .'         |   |____
+       ' ' ' '              ''''
+  original image      taking every 2nd  taking every 1st
+```
+
+The following diagram shows the principle of aliasing with a mathematical function:
 
 ```
 ^       original                     sampling period