#Elements in the human Body
#chemical symbols
symbols = c("O", "C", "H", "N", "Ca", "P", "K", "S", "Na", "Cl", "Mg")
#chemical names
names = c("Oxygen", "Carbon", "Hydrogen", "Nitrogen", "Calcium", "Phosphorus", 
          "Potassium", "Sulfur", "Sodium", "Chlorine", "Magnesium")
#atomic numbers
number = c(8, 6, 1, 7, 20, 15, 19, 16, 11, 17, 12)
#percentage by weight in human body
percents = c(65, 18.5, 9.5, 3.3, 1.5, 1.0, 0.4, 0.3, 0.2, 0.2, 0.1)
# combine into a data frame
body = data.frame(symbols, names, number, percents)
# make into a pie chart
#cex controls font size
#radius the size of the pie chart
pie(body$percents, labels = body$symbols, cex=0.5, radius= 1.05, 
    main="Elements in the Body",col=rainbow(11))
### 
# too many overlapping labels
###
# use legend instead of labels
#
pie(body$percents, cex=0.5, radius= 0.95, 
    main="Elements in the Body",col=rainbow(11))
legend("topright", legend=body$symbols, cex = 0.8, fill=rainbow(11))
###
# install the plotrix libary
# try a #3d version
# can alos just check it under Packages 
#
library(plotrix)
#
pie3D(body$percents, labels = body$symbols, cex=0.5, radius= 1.05, 
    main="Elements in the Body",col=rainbow(11))
#
# try legend instead of label 
#
pie3D(body$percents, cex=0.5, radius= 0.95, 
    main="Elements in the Body",col=rainbow(11))
legend("topright", legend=body$symbols, cex = 0.8, fill=rainbow(11))