Minimal window managers written with xlib

Still learning to write my own WM. What are some small WMs (500 lines max) whose source code I can study? I am looking for WMs that are easy to understand but still demonstrate all the key concepts (Substructure redirect, key grabbings, and maybe databases?). Ones like DWM are WAY too complicated for me to pick up... but ones like TinyWM, which has only 50 lines of source code, do not teach anything either... I know the very basics of Xlib (event handling, drawing, and just learning the resource manager) and am looking to advance my knowledge. Please help...