I bought my daughter one of those little quadrocopters from eBay. It was a lot of fun but the battery seems to have died. I found a replacement on eBay for a couple of dollars, which arrived today. Unfortunately it was slightly larger than the original.

I thought this wouldn’t be a problem so I just cut some bits out of the chassis of the quadrocopter and jammed it in.

I think I might have underestimated how narrow the performance envelope of the thing is, because instead of zipping around the room it now does this.  😦