### Theory:

Tetrominoes, in general, are classified into different types based on the alignment of the four-unit squares present in it. They are orthogonal.

Based on the alignments the tetrominoes are classified into five base types namely,

- Straight-Tetromino
- Square-Tetromino
- \(L\)-Tetromino
- \(Z\)-Tetromino
- \(T\)-Tetromino

**Rotational Properties of Tetrominoes:**

- We represent these five tetrominoes in various ways based on their angle of rotation.
- When we rotate the tetrominoes in \(90\) degrees clockwise or anti-clockwise direction, it begins to produce different projections of their base types.
- Even if we rotate tetrominoes to different angles, they remain at their same base type.
- Some tetrominoes exhibit Rotational-Symmetry.

Rotational-Symmetry is the property a shape has when it looks the same after some rotation by a partial turn, and it is the number of distinct orientations in which it seems the same for each rotation.

**The different**tetrominoes

**obtained after**angular rotations

**are given below:**

**Straight-Tetromino**:

- The Straight-Tetromino exhibits \(2\)fold Rotational-Symmetry. That is, the Straight-Tetromino obtains the same shape \(2\) times while undergoing a rotation of \(90\) degrees till it reaches the original shape.

**Square-Tetromino**:

- The Square-Tetromino exhibits \(4\)fold- Rotational-Symmetry. That is, the Square-Tetromino obtains the same shape \(4\) times while undergoing a rotation of \(90°\) till it reaches the original shape.

**L-Tetromino**:

**Z-Tetromino**:

**T-Tetromino**: