Frans van Schooten developed the Cartesian Plane in 1649 as a tool for explaining Rene Descarte's brilliant *La Géométrie*.
Centuries later, I think it could stand some improving. First, fix the labelling of the quandrants.
Get rid of the Roman numerals. Instead, use Hindu-Arabic numerals. Start the numbering with `0`

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The two most significant bits of an angle in cycles give the quadrant.

Second, make the angles proceed in a clockwork fashion. My reservation about this change in direction is that analog clock faces are obsolete. I don't know if future children will think of clockwise rotation as a preferred kind of rotation.