shape argument doesn't work

[goushengConnelly]

I used this funtion within Rstudio markdown. The cloud picture just show up as rectangular shape. When I try to change the shape arg to "star" or "circle", it cannot work, the result is still same.

[goushengConnelly]

sorry，it seems that I got too much words to show in a specific shape so they filled all empty space.

[EarlGlynn]

So how can the number of words be restricted so the shape works?

[goushengConnelly]

I used %>% top_n() to only focus on like top 150 words.