Just to fill in the blanks, here's what IDL does: IDL> a = [[1,2,3,4], $ IDL> [5,6,7,8], $ IDL> [9,10,11,12], $ IDL> [13,14,15,16]] IDL> print,a 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 IDL> print, a[[1,3],[0,3]] 2 16 --jh--