The Gerrit Noordzij cube
The animated cube it the ultimate result of Gerrit’s theory building up over the years. Originally starting as two squares, he combined the separate principles of contrast later by interpolating between them.
Just van Rossum animated the cube in Daily Drawbot, showing what is behind the layers. As static image (e.g. used on the cover of the Gerrit’s “The Stroke of the Pen“) most of the layers at the back are hidden. The squares are respectively called translation (front) and expansion (back), names for the construction of thick-thin in letters. Translation relates to broad nib pencils where expansion is based on the contrast created by flexible sharp nib pencils.