1 black polo shirt 2 to 3 times larger than your actual size
1 black polo shirt large enough to cover your head
5 feet (1.5 meters) of bias tape in the house color of your choice
2 feet (60.96 cm) of black ribbon
Try on the larger shirt and cut it as shown in Figure 1, making sure to cut off the neck and not to cut the back.
Sew along the dotted line shown in Figure 2.
And that's it - you now have a lovely Hogwarts Robe-like shirt!!!
© Catyblue's tutorial was taken with permission from sewingapprentice.blogspot.com.