The above is a good visualization of a derivation for a specific sentence in a context free language. You can find many more on Google Images by searching "context free grammar."
Let's consider the language $\{a^nb^nc^n : n>0\}$ for which no CFG exists but a RCG does. What does the visualization for the parse structure of the sentence "aaaaabbbbbccccc" look like? You can draw the visualization in MS Paint: I don't care how ugly it is as long as it isn't confusing. But you must submit a picture for an answer.