NONE!
I can see none pipes.
Thats not because they are not pipes (although it is true that they are not), but I suffer from 'pipe-blindness'. I cannot see any pipes¹. Ever².
¹This may not actually be true.
²Or this.
(
Lumpbucket tekcubpmuL,
Sun 14 Apr 2002, 20:38,
archived)