LSPDriver.kt

fun main() {
    val rectangle = Rectangle()
    rectangle.setHeight(5)
    rectangle.setWidth(2)

    val rectangleCheck = rectangle.area() == 10 // true

    val square: Rectangle = Square()
    square.setHeight(5) // width is also set to 5
    square.setWidth(2) // height is also set to 2

    val squareCheck = square.area() == 10 // false - not substitutable
}