- \(m × n\) Representation of rectangles.
- "\(m\)" is the number of rows in a rectangle.
- "\(n\)" is the number of columns in a rectangle.
\(3 × 7\) rectangle:
- It is impossible to fill up the rectangle by using all the \(5\)-Tetromino types once, because of using the \(T\)-Tetromino which has its center square covered by the other three squares (in three sides).
- It is possible to fill up the rectangle when each of the \(5\)-Tetromino is used twice.