"A simple reflective object kernel" explains ObVlisp a simple reflective kernel and it shows how to build step by step this kernel based on two classes: Object and Class. Booklet written by S. Ducasse. page 
, page , github
HTML5 mp4 http://rmod-pharo-mooc.lille.inria.fr/MOOC/PharoMOOC-Videos/EN/Week7/C019SD-W7-S3-EN-V1.mp4 Understanding Metaclasses