Add quizzes for examples

[skeqiqevian]

Originally motivated by creating examples for Mario's scheduling editor user study, this commit adds three quizzes in the example directory.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 88.07%. Comparing base (2372d0c) to head (8e0b2de).
Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #690      +/-   ##
==========================================
+ Coverage   88.00%   88.07%   +0.07%     
==========================================
  Files          86       92       +6     
  Lines       20965    21303     +338     
==========================================
+ Hits        18450    18763     +313     
- Misses       2515     2540      +25     

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