weight / number / code / to pile / to stack / classifier for length or distance (yard), happenings etc
码
=
石
+
马
:
Just when Mahatma Gandhi (m) and the unicorn (马) entered the ashram (a3) a giant rock (石) fell down and trapped them inside. There is an inscription written on it: if they ever want to leave, they will have to find the secret number (码) and say it out loud. There is also a hint: "how many roads must a man walk down?"