Toilet tank sink

Recently my place got a new bathroom installed; it's been lacking a sink however, so use has been a bit limited.

Rather than plumbing + affixing a new sink, we heard about these weird sink things that mount on the toilet tank. For the very tiny bathroom that this is, it seemed like a perfect solution.

Got it ordered, it arrived and lo and behold, it didn't fit! The top of the toilet tank was too slim and the sink just kinda rocked around:

Fortunately I had some wood lying around, so I set about it with a jigsaw:

Success!

Finally, turns out nail polish remover gets errant sharpie marker off of plastic; who knew?