Comma

      cube    ⍝ 3D array
1 2
3 4
   
5 6
7 8
      , cube
1 2 3 4 5 6 7 8

      ,[2 3] cube    ⍝ Ravel with axes
1 2 3 4
5 6 7 8

      ,[1.5]'ABC'
A
B
C

      1 2 3 , 4 5 6
1 2 3 4 5 6

      cube , 99
1 2 99
3 4 99
      
5 6 99
7 8 99

      1 2 3 ,[0.5] 4 5 6   ⍝ Laminate
1 2 3
4 5 6