The following text was written to the standard output stream when the ShapesThing.java Shapes program was executed from IntelliJ.
square = < Square: side=400.0>
area of square = 160000.0
perimeter of square = 1600.0
diagonal of square = 565.685424949238
disk = Circle: radius=200.0>
area of disk = 125663.70614359173
perimeter of disk = 1256.6370614359173
diamond = < Square: side=282.842712474619>
area of diamond = 80000.0"