PPT Slide
Permission to Draw different pictures:
“ It is not necessary for the reader to confine his illustrations to the commands in the text. He may wander at will, inventing his own illustrations, either consistent or inconsistent with the textual commands. Only thus, by his own explorations, will he come to see distinctly the bounds or laws of the world from which the mathematician is speaking.”
—G. Spencer Brown, Laws of Form, p. 79.