Migration level must be such that ⎕ML≥1 (otherwise see Type).
Y may be any array, R is a simple vector created from all the elements of Y in ravel order.
⎕ML←1 ⍝ Migration level 1 MAT←2 2⍴'MISS' 'IS' 'SIP' 'PI' ⋄ MAT MISS IS SIP PI ∊MAT MISSISSIPPI M←1 (2 2⍴2 3 4 5) (6(7 8)) M 1 2 3 6 7 8 4 5 ∊M 1 2 3 4 5 6 7 8