How do you append blocks to a block?

Hello, Suppose you have a block, lol: [1 2 3]. How can you add to that block to make it lol: [1 [1 2 3] 2 [2 3 1] 3 [3 1 2]] ?

The magic refinement to keep a block as a block when adding it to a block is /ONLY lol: copy [1 2 3] insert/only at lol 2 [1 2 3] insert/only at lol 4 [2 3 1] append/only lol [3 1 2] probe lol == [1 [1 2 3] 2 [2 3 1] 3 [3 1 2]]

In some cases, you may also want to use 'reduce to form nested blocks directly: x: [1 2 3] y: [2 3 1] z: [3 1 2] lol: reduce [1 x 2 y 3 z] == [1 [1 2 3] 2 [2 3 1] 3 [3 1 2]]

And to build on Sunanda's example a bit: lol: copy [1 2 3] x: copy [[1 2 3][2 3 1][3 1 2]] repeat i length? lol [insert/only at lol i * 2 x/:i] lol == [1 [1 2 3] 2 [2 3 1] 3 [3 1 2]]