[amibroker] Help needed for "Highest / Lowest value of the last n-bars" problem

[kose_u]

Hi,
I am trying to have two additional values for each value in any chart, 
which show -for that bar of the chart- "this bar has the largest value 
of last x bars and has the lowest value of the last y bars".
I remember once to see such a formulation in somewhere -may be in this 
list or in reference- but cannot remember/find where.
I would appreciate any help in case anybody solved such/similar problem
with a code or remebers such a code/solution/articel anywhere?