Just curious -- Looking outside of R with the same data...
### Stata
[![Stata boxplot][1]][1]

### SPSS
[![SPSS boxplot][2]][2]

### SAS Enterprise Guide
[![SAS Enterprise boxplot][3]][3]

### MATLAB (Statistics and Machine Learning tools)
[![Matlab boxplot][4]][4]

### Minitab
I was most curious about Minitab, but our virtual desktop access seemed to require a license. I'd be curious if somebody could fill this one in...

### Summary
I see lots of different styles, some I like a whole lot better than others, but all programs tested were happy to make boxplots with 2 data values.

  [1]: https://i.sstatic.net/HYXHn.png
  [2]: https://i.sstatic.net/VEH9v.png
  [3]: https://i.sstatic.net/vtukD.png
  [4]: https://i.sstatic.net/dxd4k.png