I had a sneak peek at APL2 on the mainframe a number of years ago and remember being shown solutions to the problem of adding a vector to a matrix. Given a←4 4 ⍴ ⍳16 The old way of adding a vector to the rows was something like a+(⍴a)⍴10 20 30 40 resulting in 11 22 33 44 15 26 37 48 19 30 ...