What am I doing wrong in this array comprehension?

General Usage
,
2

The comprehension generates the outer product of the two iterators.

julia> [(i,j) for i=1:3, j=1:3]
3×3 Matrix{Tuple{Int64, Int64}}:
 (1, 1)  (1, 2)  (1, 3)
 (2, 1)  (2, 2)  (2, 3)
 (3, 1)  (3, 2)  (3, 3)