How many ways are there to tile a $3 \times 3$ square with $4$ dominoes of size $1 \times 2$ and $1$ domino of size $1 \times 1$? Tilings that can be obtained from each other by rotating the square are considered different. Dominoes of the same size are completely identical
Problem
Source: 2020 Dürer Math Competition Finals Day2 E1 https://artofproblemsolving.com/community/c1622639_2020_
Tags: combinatorics, Tiling, tiles