Update greeksquare lecture with new visualizations (#481)

* Tom's June 16 edits of Greek square lecture

* update calculations of deactivations

* Tom's edit of Greeksquare lecture

* Tom's June 24 edits of greeksquare lecture

* Tom's edit of french revolution June 25

* update square root lecture

* update square root lecture

* Revert "Tom's edit of french revolution June 25"

This reverts commit ddeac33.

* update based on comments and fix typos

* update based on comments

* update visualization and add full stops for some sentences\

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Co-authored-by: thomassargent30 <ts43@nyu.edu>

Author: HumphreyYang