Ok, my blog was good and quiet. Sometime ago, around 1 year back, I started getting spams. I looked into the anti-spam measures. The 'math comment' seemed one of the better ones for me. It would not allow bots to post at all.
Everything became normal and I was happy.
Now, again it started raining spams a couple of weeks ago. I checked back if the 'math comment' was working, and I found it perfectly fine. So is it like bots are solving maths? How is it possible?