Function propose_moves

    ∇ Z←propose_moves State;Len;Max_Len;Moves;∆TCNT
[1]  ⍝
[2]  ⍝⍝ propose a move that makes progress (= placse more sub-cubes)
[3]  ⍝
[4]  →(State≡∆Initial_State)↓1+↑⎕LC ◊ ' No proposal (cube solved)' ◊ Z←'' ◊ →0
[5]  ∆TCNT←0 ◊ Len←1 ◊ Max_Len←↑Moves←print_level State ◊ Moves←1↓Moves
[6]  LOOP: Z←State propose_len_moves Moves Len
[7]  →(↑⍴∈Z)/0             ⍝ success
[8]  →(Max_Len > Len←Len+1)/LOOP
[9]  'No moves found' ◊ Z←0 3⍴0
    ∇