First attempt: strawberries. I found it really difficult!
Apparently the water droplet is for very extreme closeups only and magnifies quite a lot more than a regular macro lens.
I tried again with my Hero 9296 fountain pen and was really pleased with the results.
For comparison, this is what that pen looks like in normal photography:
So it's a fun technique, but a bit difficult to control. I look forward to playing with it more.