diff --git a/numpy/reverse_an_axis/README.md b/numpy/reverse_an_axis/README.md
new file mode 100644
index 0000000..0ece934
--- /dev/null
+++ b/numpy/reverse_an_axis/README.md
@@ -0,0 +1,127 @@
+# Reverse an axis
+{:.no_toc}
+
+<nav markdown="1" class="toc-class">
+* TOC
+{:toc}
+</nav>
+
+## The goal
+
+
+Questions to [David Rotermund](mailto:davrot@uni-bremen.de)
+
+## [numpy.flip](https://numpy.org/doc/stable/reference/generated/numpy.flip.html)
+
+```python
+numpy.flip(m, axis=None)
+```
+
+> Reverse the order of elements in an array along the given axis.
+> 
+> The shape of the array is preserved, but the elements are reordered.
+>
+> **m** : array_like
+>
+> Input array.
+> 
+> **axis** : None or int or tuple of ints, optional
+> 
+> Axis or axes along which to flip over. The default, axis=None, will flip over all of the axes of the input array. If axis is negative it counts from the last to the first axis.
+> 
+> If axis is a tuple of ints, flipping is performed on all of the axes specified in the tuple.
+>
+> **out** : array_like
+> 
+> A **view** of m with the entries of axis reversed. Since a view is returned, this operation is done in constant time.
+
+### 1d
+
+```python
+import numpy as np
+
+a = np.arange(0, 6)
+print(a) # -> [0 1 2 3 4 5]
+print()
+print(np.flip(a)) # -> [5 4 3 2 1 0]
+print()
+print(a[::-1]) # -> [5 4 3 2 1 0]
+```
+
+### 2d
+
+```python
+import numpy as np
+
+a = np.arange(0, 6).reshape((2, 3))
+print(a)
+print()
+print(np.flip(a))
+print()
+print(np.flip(a, axis=0))
+print()
+print(np.flip(a, axis=1))
+```
+
+Output:
+
+```python
+[[0 1 2]
+ [3 4 5]]
+
+[[5 4 3]
+ [2 1 0]]
+
+[[3 4 5]
+ [0 1 2]]
+
+[[2 1 0]
+ [5 4 3]]
+```
+
+## [numpy.rot90](https://numpy.org/doc/stable/reference/generated/numpy.rot90.html)
+
+```python
+numpy.rot90(m, k=1, axes=(0, 1))
+```
+
+> Rotate an array by 90 degrees in the plane specified by axes.
+> 
+> Rotation direction is from the first towards the second axis. This means for a 2D array with the default k and axes, the rotation will be counterclockwise.
+
+```python
+import numpy as np
+
+a = np.arange(0, 6).reshape((2, 3))
+print(a)
+print()
+print(np.rot90(a, k=1))
+print()
+print(np.rot90(a, k=2))
+print()
+print(np.rot90(a, k=3))
+print()
+print(np.rot90(a, k=4))
+print()
+```
+
+Output
+
+```python
+[[0 1 2]
+ [3 4 5]]
+
+[[2 5]
+ [1 4]
+ [0 3]]
+
+[[5 4 3]
+ [2 1 0]]
+
+[[3 0]
+ [4 1]
+ [5 2]]
+
+[[0 1 2]
+ [3 4 5]]
+```