--- Stack (A) ---
000: ["abc",[[[10]],["x"]],20]
--- Stack (B) ---
000: [[[10]],["x"]]
--- Stack (B1) ---
001: [["ab","ac"]]
000: [[[10]],["x"]]
--- Stack (C) ---
000: [[10]]
--- Stack (D) ---
000: [10]
--- Stack (E) ---
000: 10
--- Variables ---
L1 = [[[10]],["x"],["ab","ac"]]
s = "ab"