I've already done some research on this topic, but it still isn't quite clear to me.
According to this post patricia trees are radix trees with $r = 2$. Every patricia tree I've seen so far is used to store alphanumeric symbols. Assuming that there are used 8 bits to represent one symbol, $r$ is the number of bits compared and the radix of a radix tree is $2^r$ shouldn't the radix of a patricia tree be $2^8 = 256$?
If you have a look at a PATRICIA Tree with the following inputs (in this order):
According to the linked post a Patricia tree should then look like this:
smile - - - smiled - - - smiles
But intuitively (by the alphanumeric representation) it should look like this
d / smile \ s