There's apparently a cheat in The Sims 4 which allows the player to create massive structures. Not just any old structures though - we're talking garden gnomes, desks and of all things - toilets.
To make giant things in your game, PC Gamer says you need to hold down Shift and ] in order to grow almost any item in build mode to massive proportions. Thus, the images of large toilets you will see through the link.
I can only imagine the size of the ballcock, flapper, wax ring, retaining nut and floater you would need for such a monstrosity.
The only issue, which LazyGameReviews found, was that once an item, grew to a certain size, the player's Sims will no longer be able to move.
There are a couple of more issues when doing this, but at least your game will remain stable. Maxis will probably patch this out at some point, but go have fun while you can.