Once you've created a graphics layer (as described in How to add a graphics layer), you need to add graphics to it to display data. In most cases, you'll create graphics using geometries that have been created by actions such as executing a query or drawing a shape on the map.
/ Classtalk : A classroom communication system for active learning. In: Journal of Computing in Higher Education. 1996 ; Vol. 7, No. 2. pp. 3-47 @article{cc819104b3034becb09019ef6c28d94c,
Much of the class library is identical to that of Smalltalk-80: they both have objects, classes, single inheritance, blocks, garbage collections, collections, streams, and many other bits. In addition to this, GNU Smalltalk provides other classes including networking and GUI programming.