kotlin override
open class Shape { open val vertexCount: Int = 0 open fun draw() { /*...*/ } fun fill() { /*...*/ } } class Rectangle() : Shape() { override fun draw() { /*...*/ } // overrides method override val vertexCount = 4 // overrides property, can be set later } class Losange(override val vertexCount: Int = 4) : Shape // Always has 4 vertices, can't be set later