set anItem to "a"
set aList to {{"b", "a", "c", "a"}, {"a", "a", "c", "a"}, {"b", "v", "c", "a"}, {"b", "a", "c", "a"}}
set bRes to findDataFrom2DList(anItem, aList) of me
–> {{2, 1}, {4, 1}, {1, 2}, {2, 2}, {4, 2}, {4, 3}, {2, 4}, {4, 4}}

on findDataFrom2DList(anItem, aList)
　　script spd
　　　　property aList : {}
　　　　property resList : {}
　　end script
　　
　　set (aList of spd) to aList
　　set (resList of spd) to {}
　　
　　set yCount to 1
　　
　　repeat with i in (aList of spd)
　　　　
　　　　set aResList to (Bplus’s indexesOfItem:anItem inList:i inverting:false) as list
　　　　
　　　　set tmpList to {}
　　　　if aResList is not equal to {} then
　　　　　　repeat with ii in aResList
　　　　　　　　set jj to contents of ii
　　　　　　　　set the end of tmpList to {jj, yCount}
　　　　　　end repeat
　　　　　　set (resList of spd) to (resList of spd) & tmpList
　　　　end if
　　　　
　　　　set yCount to yCount + 1
　　end repeat
　　
　　return (resList of spd) –return {{x, y}…..} item list (1-based)
end findDataFrom2DList