https://imgur.com/gallery/SjYPY5h

My boy is getting big!! So I went and turned a 88 x 47 x 32 cm sterilite into a big boy enclosure. Problem is, is that the corners can lift up pretty darn high, even when the tub is clipped. I put a heavy board on one end, but I don’t know what to do for the other end.
He’s pretty dang strong, so he could escape no problem. I’ve put those black paper clips on as temporary measure, but I know I’m going to have to find a way to secure it properly. Does anyone have any tips or things I should buy?

thankfully he’s lazy, so I don’t have to worry him crawling out. But snakes are fickle creatures. He could be here one day and gone the next. It’d break my heart if he escaped...