diff --git a/compute.py b/compute.py
index b663453..34c23c0 100644
--- a/compute.py
+++ b/compute.py
@@ -1,8 +1,7 @@
 """Compute operations for matrices.
 
 This module provides public functions for matrix multiplication, transposition,
-matrix rotation, and generating 2D rotation matrices. The implementation is
-lightweight, well typed and contains detailed Google‑style documentation.
+matrix rotation, and generating 2D and 3D rotation matrices as well as projections.
 """
 
 from __future__ import annotations
@@ -12,7 +11,7 @@ from typing import List
 
 
 def matmul(
-    matrix_a: List[List[float]], matrix_b: List[List[float]]
+        matrix_a: List[List[float]], matrix_b: List[List[float]]
 ) -> List[List[float]]:
     """Multiply two 2D matrices.
 
@@ -21,33 +20,25 @@ def matmul(
     rows in ``matrix_b``.
 
     Args:
-        matrix_a: A matrix of shape (m, n) represented as a list of m rows,
-            each a list of n floats.
-        matrix_b: A matrix of shape (n, p) represented as a list of n rows,
-            each a list of p floats.
+        matrix_a: A matrix of shape (m, n) represented as a list of m rows.
+        matrix_b: A matrix of shape (n, p) represented as a list of n rows.
 
     Returns:
-        A new matrix of shape (m, p) containing the product
-        ``matrix_a @ matrix_b``.
+        A new matrix of shape (m, p) containing the product ``matrix_a @ matrix_b``.
 
     Raises:
-        ValueError: If either matrix is empty or if the column count of
-        ``matrix_a`` does not match the row count of ``matrix_b``.
+        ValueError: If either matrix is empty or dimensions do not match.
     """
-
-    # SCHRITT 1: Validierung – Prüfen, ob die Matrizen überhaupt Daten enthalten
     if not matrix_a or not matrix_b:
         raise ValueError("Input matrices must not be empty.")
 
     n_cols_a = len(matrix_a[0])
 
-    # SCHRITT 2: Konsistenzprüfung für Matrix A
     if any(len(row) != n_cols_a for row in matrix_a):
         raise ValueError("All rows of matrix_a must have the same number of columns.")
 
     n_rows_b = len(matrix_b)
 
-    # SCHRITT 3: Mathematische Regel prüfen: Spalten von A müssen gleich Zeilen von B sein
     if n_cols_a != n_rows_b:
         raise ValueError(
             f"Matrix dimension mismatch: matrix_a columns {n_cols_a} != matrix_b rows {n_rows_b}"
@@ -55,15 +46,13 @@ def matmul(
 
     n_cols_b = len(matrix_b[0])
 
-    # SCHRITT 4: Konsistenzprüfung für Matrix B
     if any(len(row) != n_cols_b for row in matrix_b):
         raise ValueError("All rows of matrix_b must have the same number of columns.")
 
-    # SCHRITT 5: Eigentliche Matrixmultiplikation (Skalarprodukt der Zeilen und Spalten)
     result: List[List[float]] = []
-    for i in range(len(matrix_a)):  # Gehe jede Zeile von Matrix A durch
+    for i in range(len(matrix_a)):
         row: List[float] = []
-        for j in range(n_cols_b):  # Gehe jede Spalte von Matrix B durch
+        for j in range(n_cols_b):
             elem = sum(matrix_a[i][k] * matrix_b[k][j] for k in range(n_cols_a))
             row.append(elem)
         result.append(row)
@@ -72,18 +61,7 @@ def matmul(
 
 
 def transpose(matrix: List[List[float]]) -> List[List[float]]:
-    """Return the transpose of a 2‑D matrix.
-
-    Args:
-        matrix: A non‑empty matrix represented as a list of rows.
-
-    Returns:
-        A new matrix where rows become columns.
-
-    Raises:
-        ValueError: If the input matrix is empty or ragged.
-    """
-
+    """Return the transpose of a 2D matrix."""
     if not matrix:
         raise ValueError("Cannot transpose an empty matrix.")
 
@@ -97,27 +75,11 @@ def transpose(matrix: List[List[float]]) -> List[List[float]]:
 
 
 def rotate_clockwise(matrix: List[List[float]]) -> List[List[float]]:
-    """Rotate a square matrix 90 degrees clockwise.
-
-    The function works for any rectangular matrix but will produce a matrix
-    of dimensions (cols, rows).
-
-    Args:
-        matrix: A non‑empty matrix.
-
-    Returns:
-        The rotated matrix.
-
-    Raises:
-        ValueError: If the matrix is empty.
-    """
-
+    """Rotate a square matrix 90 degrees clockwise."""
     if not matrix:
         raise ValueError("Cannot rotate an empty matrix.")
 
-    n_rows = len(matrix)
     n_cols = len(matrix[0])
-
     if any(len(row) != n_cols for row in matrix):
         raise ValueError("All rows of the matrix must have the same number of columns.")
 
@@ -126,42 +88,52 @@ def rotate_clockwise(matrix: List[List[float]]) -> List[List[float]]:
 
 
 def rot_2D(theta: float) -> List[List[float]]:
-    """Return the 2D rotation matrix for a given angle.
-
-    Calculates the 2x2 rotation matrix used in computer graphics to rotate a point
-    counterclockwise around the origin by angle theta (in radians).
-
-    Args:
-        theta: The rotation angle in radians.
-
-    Returns:
-        A 2x2 rotation matrix represented as a list of lists of floats:
-        [[cos(theta), -sin(theta)],
-         [sin(theta),  cos(theta)]]
-    """
-    c = math.cos(theta)
-    s = math.sin(theta)
+    """Return the 2D rotation matrix for a given angle in degrees."""
+    rad = math.radians(theta)
+    c = math.cos(rad)
+    s = math.sin(rad)
     return [[c, -s], [s, c]]
 
 
+def rot_3D(angle: float, axis: str) -> list[list[float]]:
+    """Erzeugt eine 3D-Rotationsmatrix um die angegebene Achse ('x', 'y' oder 'z')."""
+    rad = math.radians(angle)
+    c, s = math.cos(rad), math.sin(rad)
+
+    axis = axis.lower()
+    if axis == 'x':
+        return [
+            [1.0, 0.0, 0.0],
+            [0.0, c, -s],
+            [0.0, s, c]
+        ]
+    elif axis == 'y':
+        return [
+            [c, 0.0, s],
+            [0.0, 1.0, 0.0],
+            [-s, 0.0, c]
+        ]
+    elif axis == 'z':
+        return [
+            [c, -s, 0.0],
+            [s, c, 0.0],
+            [0.0, 0.0, 1.0]
+        ]
+    else:
+        raise ValueError("Achse muss 'x', 'y' oder 'z' sein.")
+
+
+def project_ortho(point: tuple[float, float, float], scale: float = 1.0) -> tuple[float, float]:
+    """Projiziert einen 3D-Punkt orthogonal auf eine 2D-Ebene und skaliert ihn."""
+    x, y, z = point
+    return (x * scale, y * scale)
+
+
 if __name__ == "__main__":
-    # Testdaten für die Demonstration
     a = [[1, 2, 3], [4, 5, 6]]
     b = [[7, 8], [9, 10], [11, 12]]
 
-    print("matmul(a, b):")
-    print(matmul(a, b))
+    print("matmul(a, b):", matmul(a, b))
+    print("transpose(a):", transpose(a))
 
-    print("transpose(a):")
-    print(transpose(a))
-
-    c = [[1, 2], [3, 4], [5, 6]]
-    print("rotate_clockwise(c):")
-    print(rotate_clockwise(c))
-
-    # Demonstration von rot_2D (z. B. 90 Grad = pi / 2 Radiant)
-    angle = math.pi / 2
-    print(f"rot_2D (pi / 2 radians / 90 degrees):")
-    rotation_matrix = rot_2D(angle)
-    for row in rotation_matrix:
-        print([round(val, 4) for val in row])
+    # Teste deine Tests mit: python -m pytest
\ No newline at end of file
diff --git a/install_dependencies.py b/install_dependencies.py
new file mode 100644
index 0000000..5a20e39
--- /dev/null
+++ b/install_dependencies.py
@@ -0,0 +1,146 @@
+#!/usr/bin/env python3
+"""Installiert die Abhängigkeiten aus pyproject.toml in die aktuelle Python-Umgebung.
+
+Ersatz für "Install requirements" aus PyCharm, wenn das Projekt eine pyproject.toml
+statt einer requirements.txt hat. Kein Build, keine besondere Projektstruktur nötig,
+nur Standardbibliothek (Python >= 3.11).
+
+Benutzung:
+  In PyCharm: Rechtsklick auf diese Datei -> Run 'install_dependencies'
+  Im Terminal (venv aktiv): python install_dependencies.py
+
+Ohne Parameter wird ALLES installiert:
+  [project].dependencies + alle [project.optional-dependencies] + alle [dependency-groups]
+
+Abweichendes Verhalten:
+  python install_dependencies.py --extra dev        nur Basis + Extra "dev"
+  python install_dependencies.py --group test       nur Basis + Gruppe "test"
+  python install_dependencies.py --no-main --group dev
+  python install_dependencies.py --list             nur anzeigen, nichts installieren
+  python install_dependencies.py --write            requirements.txt schreiben statt installieren
+  python install_dependencies.py --write -o reqs.txt
+"""
+from __future__ import annotations
+
+import sys
+
+if sys.version_info < (3, 11):
+    sys.exit("Dieses Skript braucht Python 3.11 oder neuer (tomllib). "
+             f"Aktuell: {sys.version.split()[0]}")
+
+import argparse
+import subprocess
+import tempfile
+import tomllib
+from pathlib import Path
+
+PROJECT_DIR = Path(__file__).resolve().parent
+
+
+def resolve_group(groups: dict, name: str, seen: set[str] | None = None) -> list[str]:
+    """Löst eine Dependency-Group inkl. {include-group = "..."} rekursiv auf."""
+    seen = set() if seen is None else seen
+    if name in seen:
+        raise ValueError(f"Zyklische include-group: {name}")
+    if name not in groups:
+        raise KeyError(f"Dependency-Group '{name}' nicht gefunden")
+    seen.add(name)
+    result: list[str] = []
+    for entry in groups[name]:
+        if isinstance(entry, str):
+            result.append(entry)
+        elif isinstance(entry, dict) and "include-group" in entry:
+            result.extend(resolve_group(groups, entry["include-group"], seen))
+    return result
+
+
+def collect(data: dict, extras: list[str], groups: list[str], no_main: bool) -> list[str]:
+    project = data.get("project", {})
+    optional = project.get("optional-dependencies", {})
+    dep_groups = data.get("dependency-groups", {})
+    deps: list[str] = []
+
+    if not no_main:
+        deps.extend(project.get("dependencies", []))
+    for extra in extras:
+        if extra not in optional:
+            raise KeyError(f"Optional-Dependency '{extra}' nicht gefunden")
+        deps.extend(optional[extra])
+    for group in groups:
+        deps.extend(resolve_group(dep_groups, group))
+
+    # Duplikate entfernen, Reihenfolge behalten
+    return list(dict.fromkeys(d.strip() for d in deps if d.strip()))
+
+
+def main() -> int:
+    p = argparse.ArgumentParser(description=__doc__, formatter_class=argparse.RawDescriptionHelpFormatter)
+    p.add_argument("-p", "--pyproject", type=Path, default=PROJECT_DIR / "pyproject.toml",
+                   help="Pfad zur pyproject.toml (Standard: neben diesem Skript)")
+    p.add_argument("--extra", action="append", default=None,
+                   help="nur diese optional-dependencies (mehrfach möglich)")
+    p.add_argument("--group", action="append", default=None,
+                   help="nur diese dependency-groups (mehrfach möglich)")
+    p.add_argument("--no-main", action="store_true", help="[project].dependencies weglassen")
+    p.add_argument("--list", action="store_true", help="Abhängigkeiten nur anzeigen")
+    p.add_argument("--write", action="store_true", help="requirements-Datei schreiben statt installieren")
+    p.add_argument("-o", "--output", type=Path, default=PROJECT_DIR / "requirements.txt",
+                   help="Zieldatei für --write")
+    args = p.parse_args()
+
+    if not args.pyproject.exists():
+        print(f"{args.pyproject} nicht gefunden", file=sys.stderr)
+        return 1
+    data = tomllib.loads(args.pyproject.read_text(encoding="utf-8"))
+    all_extras = list(data.get("project", {}).get("optional-dependencies", {}))
+    all_groups = list(data.get("dependency-groups", {}))
+
+    # Ohne --extra/--group: alles. Mit einem davon: nur das Gewählte.
+    selective = args.extra is not None or args.group is not None
+    extras = (args.extra or []) if selective else all_extras
+    groups = (args.group or []) if selective else all_groups
+
+    try:
+        deps = collect(data, extras, groups, args.no_main)
+    except (KeyError, ValueError) as e:
+        print(f"Fehler: {e.args[0]}", file=sys.stderr)
+        print(f"  Vorhandene --extra: {', '.join(all_extras) or '(keine)'}", file=sys.stderr)
+        print(f"  Vorhandene --group: {', '.join(all_groups) or '(keine)'}", file=sys.stderr)
+        return 1
+
+    parts = ([] if args.no_main else ["Basis"]) + [f"extra:{e}" for e in extras] + [f"group:{g}" for g in groups]
+    print(f"Auswahl: {', '.join(parts) or '(nichts)'}")
+
+    if args.list:
+        print("\n".join(deps) or "(keine Abhängigkeiten)")
+        return 0
+
+    content = f"# Automatisch erzeugt aus {args.pyproject.name} – nicht von Hand bearbeiten\n" + "\n".join(deps) + "\n"
+
+    if args.write:
+        args.output.write_text(content, encoding="utf-8")
+        print(f"{len(deps)} Abhängigkeiten -> {args.output}")
+        return 0
+
+    if not deps:
+        print("Keine Abhängigkeiten gefunden – nichts zu tun.")
+        return 0
+
+    if sys.prefix == sys.base_prefix:
+        print("WARNUNG: Es ist kein virtuelles Environment aktiv – es wird in die globale "
+              f"Python-Installation installiert:\n  {sys.prefix}", file=sys.stderr)
+        if sys.stdin.isatty() and input("Trotzdem fortfahren? [j/N] ").strip().lower() not in ("j", "ja", "y", "yes"):
+            return 1
+
+    with tempfile.NamedTemporaryFile("w", suffix=".txt", delete=False, encoding="utf-8") as tmp:
+        tmp.write(content)
+        tmp_path = Path(tmp.name)
+    try:
+        print(f"Installiere {len(deps)} Abhängigkeiten in {sys.prefix}\n")
+        return subprocess.call([sys.executable, "-m", "pip", "install", "-r", str(tmp_path)])
+    finally:
+        tmp_path.unlink(missing_ok=True)
+
+
+if __name__ == "__main__":
+    raise SystemExit(main())
diff --git a/pyproject.toml b/pyproject.toml
index 3a776b1..6d49d24 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,4 +1,6 @@
 [project]
 name = "matrixmania"
 version = "0.1.0"
-dependencies = ["tabulate", "ruff"]
\ No newline at end of file
+dependencies = ["tabulate", "ruff"]
+[project.optional-dependencies]
+dev = ["pytest", "ruff", "pytest-cov"]
\ No newline at end of file
diff --git a/test/test_matrixmania/test_projection.py b/test/test_matrixmania/test_projection.py
new file mode 100644
index 0000000..e89a79d
--- /dev/null
+++ b/test/test_matrixmania/test_projection.py
@@ -0,0 +1,25 @@
+import pytest
+from compute import project_ortho
+
+
+def test_project_ortho_default_scale():
+    # Arrange
+    point = (1.0, 2.0, 3.0)
+
+    # Act
+    result = project_ortho(point)
+
+    # Assert
+    assert result == (1.0, 2.0)
+
+
+def test_project_ortho_scale_100():
+    # Arrange
+    point = (1.0, 2.0, 3.0)
+    scale = 100.0
+
+    # Act
+    result = project_ortho(point, scale)
+
+    # Assert
+    assert result == (100.0, 200.0)
\ No newline at end of file
diff --git a/test/test_matrixmania/test_rot.py b/test/test_matrixmania/test_rot.py
new file mode 100644
index 0000000..f1f5981
--- /dev/null
+++ b/test/test_matrixmania/test_rot.py
@@ -0,0 +1,30 @@
+import pytest
+from compute import rot_2D, rot_3D
+
+
+def test_rot_2D_90_degrees():
+    # Arrange
+    angle = 90.0
+
+    # Act
+    matrix = rot_2D(angle)
+
+    # Assert (bei 90°: cos(90)=0, sin(90)=1)
+    assert pytest.approx(matrix[0][0], abs=1e-5) == 0.0
+    assert pytest.approx(matrix[0][1], abs=1e-5) == -1.0
+    assert pytest.approx(matrix[1][0], abs=1e-5) == 1.0
+    assert pytest.approx(matrix[1][1], abs=1e-5) == 0.0
+
+
+def test_rot_3D_z_axis_90_degrees():
+    # Arrange
+    angle = 90.0
+    axis = 'z'
+
+    # Act
+    matrix = rot_3D(angle, axis)
+
+    # Assert
+    assert pytest.approx(matrix[0][0], abs=1e-5) == 0.0
+    assert pytest.approx(matrix[0][1], abs=1e-5) == -1.0
+    assert pytest.approx(matrix[2][2], abs=1e-5) == 1.0
\ No newline at end of file