The bronze script of the character Close is
The left one: there is a door 門, and there are two wood vertical bars touching the door and the ground. 《象形字典》 - The Dictionary of Pictography explains that the character is mistakenly not having the two bars horizontally joint in the middle, just like the locker we use right now.
I disagree with the dictionary's explanation. The bronze script time is about 3000 years ago, the metal was not widely used for normal people. So people didn't have metal locker. They had to use wood bars to block the door as lock.
The right one, there is 串 under 門, which is a lock-alike. I think that the two circles made from rattan are used to fasten the two doors with the bar.
The big seal script of the character is
which is similar to the left one of bronze script above. The dots in the middle of the two vertical bars are not clear, but I guess that are forked sticks, the dots are the joints. The forked sticks can have better support the door.
The small seal script of the character is