This example helped me: [r] > circle mul 2 3.14 r > perimeter mul 3.14 r r > area The first line creates an “abstract” object named circle. It is abstra

This example helped me: [r] > circle mul 2 3.14 r > perimeter mul 3.14 r r > area The first line creates an “abstract” object named circle. It is abstract, because one of its attributes r is “free”. It’s not specified in this object and that’s why the object can’t be used as is, it has to be copied with r specified. For example, this is the circle c with the radius 30: circle 30 > c ( Which would be like c=new circle(30) ) https://www.yegor256.com/2020/11/24/objects-without-methods.html https://www.yegor256.com/2020/11/24/objects-without-methods....