For my unexperienced sewing eyes this reversible bag does not only look very nice but also rather easy to make :)
Links:
Reversible Bag (Wi-Wa-Wende-Tasche (Anleitung)) (German)
=> this is the approved German translation of the English Reversible Shoulder Bag Tutorial
via: Polly Pünktchen: Wi-Wa-Wende-Tasche (Anleitung)