# --Graphical Models-- Understanding blocked paths and conditional independence

I am quite confused by this slide from a course I found on the internet from UCL on Graphical Models. Here is the slide:

I would like to confirm whether I have correct understanding:

In the following picture, the set of nodes $$\mathcal{X,Y,C}$$ are:

• $$\mathcal{X}=\{1\}$$
• $$\mathcal{Y}=\{2\}$$
• $$\mathcal{C}=\{4\}$$

I coloured $$4$$ because it's in the conditioning set. So, is $$1$$ and $$2$$ blocked by $$4$$ and $$1$$ and $$2$$ are independent given $$4$$?

If anyone can give more examples that would help a lot