An activity based on sunshine is maybe a little optimistic for midwinter in the northern hemisphere, but this will still work, though might take a while longer.
If you've seen the old fashioned blue-prints then you'll be familiar with the effects of this process.
In essence, you used an object to provide a resist on paper of fabric that has been treated with a light sensitive chemical. The sunlight can't get to the area beneath the object, so that part stays pale. The areas exposed to sunlight turn blue. When you rinse the paper the reaction is halted, and the image is permanent.
You can buy paper pre-treated from Amazon, or if you're in the US direct from a company called Sunprint. If you fancy doing this to fabric, or just making your own it's also possible to buy the chemicals you need.
This post is part of my advent calendar 2016. Every day in December we're saying so long to 2016 by embracing learning, knowledge and creativity. Each day there will be a new post with a new skill or craft. You can read all the past posts here.