Since almost 9 years ago, Science Stack Exchanges have been advertising other Science Stack Exchanges that are still in Beta:
Currently we are using the default image automatically generated by Area51, but it seems it would be much nicer if we had a custom logo.
Update: Our Community Ad on Physics.SE (slightly different from the Area51-generated logo) is performing worse than all of the other community ads in terms of clicks/day (in some cases other ads are getting 2x as many clicks/day as us):
Is anyone here able to make one? Perhaps people can answer with logo ideas?