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A 2x2 grid covered in triangles

Source: 43rd International Tournament of Towns, Senior A-Level P7, Fall 2021

February 18, 2023
combinatoricscombinatorial geometryTournament of Towns

Problem Statement

A checkered square of size 2×22\times2 is covered by two triangles. Is it necessarily true that:
[*]at least one of its four cells is fully covered by one of the triangles; [*]some square of size 1×11\times1 can be placed into one of these triangles?
Alexandr Shapovalov