Made a heap, like the piper round the corner (5)
I believe the answer is:
piled
'made a heap' is the definition.
(I've seen this in another clue)
'like the piper round the corner' is the wordplay.
'like the piper' becomes 'pied-' (I've seen this in another clue).
'round' is an insertion indicator.
'the corner' becomes 'l' (I can't justify this - if you can you should give a lot more credence to this answer).
'pied' placed around 'l' is 'PILED'.
Can you help me to learn more?
(Other definitions for piled that I've seen before include "Heaped" , "put in a heap" , "Arranged in stacks" .)