diff --git a/tech/animation.wiki b/tech/animation.wiki
index a000232..275ace9 100644
--- a/tech/animation.wiki
+++ b/tech/animation.wiki
@@ -9,3 +9,23 @@ create the appearance of motion.
 * data-driven
 * procedural
 * simulation
+
+== perception of motion ==
+
+Humans can only process about 12 images per second. If an image moves faster
+than this, the illusion of continous motion is created.
+
+== principles of animation ==
+
+1) squash/stretch
+2) anticipation
+3) staging
+4) straight ahead action and post to pose
+5) follow through and overlapping action
+6) slow in and slow out
+7) arc
+8) secondary action
+9) timing
+10) exaggeration
+11) solid drawing
+12) appeal