[D] Interesting model design questions?

I was browsing through data science stack exchange, and I saw [this](https://datascience.stackexchange.com/questions/29345/how-to-sort-numbers-using-convolutional-neural-network):

\> *Design a convnet that sorts numbers. Operators are ReLU, Conv, and Pooling. E.g. input: 5, 3, 6, 2; output: 2, 3, 5, 6*

What are other such interesting questions? Ways to really think about how one might use / abuse / sample in interesting ways from neural networks?

abuse design machinelearning networks neural networks numbers operators pooling questions relu sample think