I saw the sword in the elaborate city world. it didn't appear in the flat world.
But, here's the problem: lag! the screen freezes. it really doesn't move after you activate the mod! and then things start moving. not good.
as an experiment, I tried these two lines of code to see if there would be any lag, because the cookie clicker mod had more code and, possibly, more to do with the lag. but, bigger'n Dallas, there's lag!
So, I found a temporary solution. Don't try to make a mod. I found some curated mods that seem to work. But, I'm going over to my classroom to see if I can actually build the mod piecemeal without the lag.
Wish me luck!