This code creates a split violin plot through ggplot2 (using ggproto()) to compare the difference in distribution among three variables.
It compares the distribution of median price paid for residential properties in local authorities in England and Wales, between freehold and leashold aswell as new and existing. The data is from the year ending September 2017.
The price paid data was pulled from ONS House Price Statistics for Small Areas - https://www.ons.gov.uk/peoplepopulationandcommunity/housing/datasets/housepricestatisticsforsmallareasinenglandandwalessupplementarydatasets
Special credit goes to @jan-glx on SO for the split violin plot code.