Russian Dolls are a set of wooden dolls of decreasing size placed one inside another.Some of our posts have an interactive "Russian Dolls Format", which means - just like Russian dolls - you can see more and more of the text as you engage with it, answer questions and unlock the next steps.
When you answer a question correctly, the next "doll" appears. If it doesn't, then your answer is wrong. Think more and try other answers, until you succeed to unlock the next step.
If you get stuck anywhere along the way, you can ask for help in the comments.